IABSD.fr/xenocara/lib/mesa/scons/gallium.py

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• Author : jsg
  Date : 2018-10-23 06:35:32
  Hash : 19f2c52c
  Message : Merge Mesa 17.3.9 Mesa 18.x needs an ld with build-id for at least the intel code Mesa 18.2 assumes linux only memfd syscalls in intel code Tested by matthieu@, kettenis@ and myself on a variety of hardware and architectures. ok kettenis@

• lib/mesa/scons/gallium.py

• """gallium
  
  Frontend-tool for Gallium3D architecture.
  
  """
  
  #
  # Copyright 2008 VMware, Inc.
  # All Rights Reserved.
  #
  # Permission is hereby granted, free of charge, to any person obtaining a
  # copy of this software and associated documentation files (the
  # "Software"), to deal in the Software without restriction, including
  # without limitation the rights to use, copy, modify, merge, publish,
  # distribute, sub license, and/or sell copies of the Software, and to
  # permit persons to whom the Software is furnished to do so, subject to
  # the following conditions:
  #
  # The above copyright notice and this permission notice (including the
  # next paragraph) shall be included in all copies or substantial portions
  # of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  # IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  # ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  #
  
  
  import distutils.version
  import os
  import os.path
  import re
  import subprocess
  import platform as host_platform
  import sys
  import tempfile
  
  import SCons.Action
  import SCons.Builder
  import SCons.Scanner
  
  
  def symlink(target, source, env):
      target = str(target[0])
      source = str(source[0])
      if os.path.islink(target) or os.path.exists(target):
          os.remove(target)
      os.symlink(os.path.basename(source), target)
  
  def install(env, source, subdir):
      target_dir = os.path.join(env.Dir('#.').srcnode().abspath, env['build_dir'], subdir)
      return env.Install(target_dir, source)
  
  def install_program(env, source):
      return install(env, source, 'bin')
  
  def install_shared_library(env, sources, version = ()):
      targets = []
      install_dir = os.path.join(env.Dir('#.').srcnode().abspath, env['build_dir'])
      version = tuple(map(str, version))
      if env['SHLIBSUFFIX'] == '.dll':
          dlls = env.FindIxes(sources, 'SHLIBPREFIX', 'SHLIBSUFFIX')
          targets += install(env, dlls, 'bin')
          libs = env.FindIxes(sources, 'LIBPREFIX', 'LIBSUFFIX')
          targets += install(env, libs, 'lib')
      else:
          for source in sources:
              target_dir =  os.path.join(install_dir, 'lib')
              target_name = '.'.join((str(source),) + version)
              last = env.InstallAs(os.path.join(target_dir, target_name), source)
              targets += last
              while len(version):
                  version = version[:-1]
                  target_name = '.'.join((str(source),) + version)
                  action = SCons.Action.Action(symlink, "  Symlinking $TARGET ...")
                  last = env.Command(os.path.join(target_dir, target_name), last, action) 
                  targets += last
      return targets
  
  
  def msvc2013_compat(env):
      if env['gcc']:
          env.Append(CCFLAGS = [
              '-Werror=vla',
              '-Werror=pointer-arith',
          ])
  
  
  def unit_test(env, test_name, program_target, args=None):
      env.InstallProgram(program_target)
  
      cmd = [program_target[0].abspath]
      if args is not None:
          cmd += args
      cmd = ' '.join(cmd)
  
      # http://www.scons.org/wiki/UnitTests
      action = SCons.Action.Action(cmd, "  Running $SOURCE ...")
      alias = env.Alias(test_name, program_target, action)
      env.AlwaysBuild(alias)
      env.Depends('check', alias)
  
  
  def num_jobs():
      try:
          return int(os.environ['NUMBER_OF_PROCESSORS'])
      except (ValueError, KeyError):
          pass
  
      try:
          return os.sysconf('SC_NPROCESSORS_ONLN')
      except (ValueError, OSError, AttributeError):
          pass
  
      try:
          return int(os.popen2("sysctl -n hw.ncpu")[1].read())
      except ValueError:
          pass
  
      return 1
  
  
  def check_cc(env, cc, expr, cpp_opt = '-E'):
      # Invoke C-preprocessor to determine whether the specified expression is
      # true or not.
  
      sys.stdout.write('Checking for %s ... ' % cc)
  
      source = tempfile.NamedTemporaryFile(suffix='.c', delete=False)
      source.write('#if !(%s)\n#error\n#endif\n' % expr)
      source.close()
  
      pipe = SCons.Action._subproc(env, [env['CC'], cpp_opt, source.name],
                                   stdin = 'devnull',
                                   stderr = 'devnull',
                                   stdout = 'devnull')
      result = pipe.wait() == 0
  
      os.unlink(source.name)
  
      sys.stdout.write(' %s\n' % ['no', 'yes'][int(bool(result))])
      return result
  
  def check_header(env, header):
      '''Check if the header exist'''
  
      conf = SCons.Script.Configure(env)
      have_header = False
  
      if conf.CheckHeader(header):
          have_header = True
  
      env = conf.Finish()
      return have_header
  
  def check_functions(env, functions):
      '''Check if all of the functions exist'''
  
      conf = SCons.Script.Configure(env)
      have_functions = True
  
      for function in functions:
          if not conf.CheckFunc(function):
              have_functions = False
  
      env = conf.Finish()
      return have_functions
  
  def check_prog(env, prog):
      """Check whether this program exists."""
  
      sys.stdout.write('Checking for %s ... ' % prog)
  
      result = env.Detect(prog)
  
      sys.stdout.write(' %s\n' % ['no', 'yes'][int(bool(result))])
      return result
  
  
  def generate(env):
      """Common environment generation code"""
  
      # Tell tools which machine to compile for
      env['TARGET_ARCH'] = env['machine']
      env['MSVS_ARCH'] = env['machine']
  
      # Toolchain
      platform = env['platform']
      env.Tool(env['toolchain'])
  
      # Allow override compiler and specify additional flags from environment
      if 'CC' in os.environ:
          env['CC'] = os.environ['CC']
      if 'CFLAGS' in os.environ:
          env['CCFLAGS'] += SCons.Util.CLVar(os.environ['CFLAGS'])
      if 'CXX' in os.environ:
          env['CXX'] = os.environ['CXX']
      if 'CXXFLAGS' in os.environ:
          env['CXXFLAGS'] += SCons.Util.CLVar(os.environ['CXXFLAGS'])
      if 'LDFLAGS' in os.environ:
          env['LINKFLAGS'] += SCons.Util.CLVar(os.environ['LDFLAGS'])
  
      # Detect gcc/clang not by executable name, but through pre-defined macros
      # as autoconf does, to avoid drawing wrong conclusions when using tools
      # that overrice CC/CXX like scan-build.
      env['gcc_compat'] = 0
      env['clang'] = 0
      env['msvc'] = 0
      if host_platform.system() == 'Windows':
          env['msvc'] = check_cc(env, 'MSVC', 'defined(_MSC_VER)', '/E')
      if not env['msvc']:
          env['gcc_compat'] = check_cc(env, 'GCC', 'defined(__GNUC__)')
      env['clang'] = check_cc(env, 'Clang', '__clang__')
      env['gcc'] = env['gcc_compat'] and not env['clang']
      env['suncc'] = env['platform'] == 'sunos' and os.path.basename(env['CC']) == 'cc'
      env['icc'] = 'icc' == os.path.basename(env['CC'])
  
      if env['msvc'] and env['toolchain'] == 'default' and env['machine'] == 'x86_64':
          # MSVC x64 support is broken in earlier versions of scons
          env.EnsurePythonVersion(2, 0)
  
      # shortcuts
      machine = env['machine']
      platform = env['platform']
      x86 = env['machine'] == 'x86'
      ppc = env['machine'] == 'ppc'
      gcc_compat = env['gcc_compat']
      msvc = env['msvc']
      suncc = env['suncc']
      icc = env['icc']
  
      # Determine whether we are cross compiling; in particular, whether we need
      # to compile code generators with a different compiler as the target code.
      hosthost_platform = host_platform.system().lower()
      if hosthost_platform.startswith('cygwin'):
          hosthost_platform = 'cygwin'
      host_machine = os.environ.get('PROCESSOR_ARCHITEW6432', os.environ.get('PROCESSOR_ARCHITECTURE', host_platform.machine()))
      host_machine = {
          'x86': 'x86',
          'i386': 'x86',
          'i486': 'x86',
          'i586': 'x86',
          'i686': 'x86',
          'ppc' : 'ppc',
          'AMD64': 'x86_64',
          'x86_64': 'x86_64',
      }.get(host_machine, 'generic')
      env['crosscompile'] = platform != hosthost_platform
      if machine == 'x86_64' and host_machine != 'x86_64':
          env['crosscompile'] = True
      env['hostonly'] = False
  
      # Backwards compatability with the debug= profile= options
      if env['build'] == 'debug':
          if not env['debug']:
              print('scons: warning: debug option is deprecated and will be removed eventually; use instead')
              print('')
              print(' scons build=release')
              print('')
              env['build'] = 'release'
          if env['profile']:
              print('scons: warning: profile option is deprecated and will be removed eventually; use instead')
              print('')
              print(' scons build=profile')
              print('')
              env['build'] = 'profile'
      if False:
          # Enforce SConscripts to use the new build variable
          env.popitem('debug')
          env.popitem('profile')
      else:
          # Backwards portability with older sconscripts
          if env['build'] in ('debug', 'checked'):
              env['debug'] = True
              env['profile'] = False
          if env['build'] == 'profile':
              env['debug'] = False
              env['profile'] = True
          if env['build'] in ('release', 'opt'):
              env['debug'] = False
              env['profile'] = False
  
      # Put build output in a separate dir, which depends on the current
      # configuration. See also http://www.scons.org/wiki/AdvancedBuildExample
      build_topdir = 'build'
      build_subdir = env['platform']
      if env['embedded']:
          build_subdir =  'embedded-' + build_subdir
      if env['machine'] != 'generic':
          build_subdir += '-' + env['machine']
      if env['build'] != 'release':
          build_subdir += '-' +  env['build']
      build_dir = os.path.join(build_topdir, build_subdir)
      # Place the .sconsign file in the build dir too, to avoid issues with
      # different scons versions building the same source file
      env['build_dir'] = build_dir
      env.SConsignFile(os.path.join(build_dir, '.sconsign'))
      if 'SCONS_CACHE_DIR' in os.environ:
          print('scons: Using build cache in %s.' % (os.environ['SCONS_CACHE_DIR'],))
          env.CacheDir(os.environ['SCONS_CACHE_DIR'])
      env['CONFIGUREDIR'] = os.path.join(build_dir, 'conf')
      env['CONFIGURELOG'] = os.path.join(os.path.abspath(build_dir), 'config.log')
  
      # Parallel build
      if env.GetOption('num_jobs') <= 1:
          env.SetOption('num_jobs', num_jobs())
  
      env.Decider('MD5-timestamp')
      env.SetOption('max_drift', 60)
  
      # C preprocessor options
      cppdefines = []
      cppdefines += [
          '__STDC_CONSTANT_MACROS',
          '__STDC_FORMAT_MACROS',
          '__STDC_LIMIT_MACROS',
          'HAVE_NO_AUTOCONF',
      ]
      if env['build'] in ('debug', 'checked'):
          cppdefines += ['DEBUG']
      else:
          cppdefines += ['NDEBUG']
      if env['build'] == 'profile':
          cppdefines += ['PROFILE']
      if env['build'] in ('opt', 'profile'):
          cppdefines += ['VMX86_STATS']
      if env['platform'] in ('posix', 'linux', 'freebsd', 'darwin'):
          cppdefines += [
              '_POSIX_SOURCE',
              ('_POSIX_C_SOURCE', '199309L'),
              '_SVID_SOURCE',
              '_BSD_SOURCE',
              '_GNU_SOURCE',
              '_DEFAULT_SOURCE',
          ]
          if env['platform'] == 'darwin':
              cppdefines += [
                  '_DARWIN_C_SOURCE',
                  'GLX_USE_APPLEGL',
                  'GLX_DIRECT_RENDERING',
              ]
          else:
              cppdefines += [
                  'GLX_DIRECT_RENDERING',
                  'GLX_INDIRECT_RENDERING',
              ]
  
          if check_header(env, 'xlocale.h'):
              cppdefines += ['HAVE_XLOCALE_H']
  
          if check_header(env, 'endian.h'):
              cppdefines += ['HAVE_ENDIAN_H']
  
          if check_functions(env, ['strtod_l', 'strtof_l']):
              cppdefines += ['HAVE_STRTOD_L']
  
      if platform == 'windows':
          cppdefines += [
              'WIN32',
              '_WINDOWS',
              #'_UNICODE',
              #'UNICODE',
              # http://msdn.microsoft.com/en-us/library/aa383745.aspx
              ('_WIN32_WINNT', '0x0601'),
              ('WINVER', '0x0601'),
          ]
          if gcc_compat:
              cppdefines += [('__MSVCRT_VERSION__', '0x0700')]
          if msvc:
              cppdefines += [
                  'VC_EXTRALEAN',
                  '_USE_MATH_DEFINES',
                  '_CRT_SECURE_NO_WARNINGS',
                  '_CRT_SECURE_NO_DEPRECATE',
                  '_SCL_SECURE_NO_WARNINGS',
                  '_SCL_SECURE_NO_DEPRECATE',
                  '_ALLOW_KEYWORD_MACROS',
                  '_HAS_EXCEPTIONS=0', # Tell C++ STL to not use exceptions
              ]
          if env['build'] in ('debug', 'checked'):
              cppdefines += ['_DEBUG']
      if platform == 'windows':
          cppdefines += ['PIPE_SUBSYSTEM_WINDOWS_USER']
      if env['embedded']:
          cppdefines += ['PIPE_SUBSYSTEM_EMBEDDED']
      if env['texture_float']:
          print('warning: Floating-point textures enabled.')
          print('warning: Please consult docs/patents.txt with your lawyer before building Mesa.')
          cppdefines += ['TEXTURE_FLOAT_ENABLED']
      env.Append(CPPDEFINES = cppdefines)
  
      # C compiler options
      cflags = [] # C
      cxxflags = [] # C++
      ccflags = [] # C & C++
      if gcc_compat:
          if env['build'] == 'debug':
              ccflags += ['-O0']
          else:
              ccflags += ['-O3']
          if env['gcc']:
              # gcc's builtin memcmp is slower than glibc's
              # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43052
              ccflags += ['-fno-builtin-memcmp']
          # Work around aliasing bugs - developers should comment this out
          ccflags += ['-fno-strict-aliasing']
          ccflags += ['-g']
          if env['build'] in ('checked', 'profile') or env['asan']:
              # See http://code.google.com/p/jrfonseca/wiki/Gprof2Dot#Which_options_should_I_pass_to_gcc_when_compiling_for_profiling?
              ccflags += [
                  '-fno-omit-frame-pointer',
              ]
              if env['gcc']:
                  ccflags += ['-fno-optimize-sibling-calls']
          if env['machine'] == 'x86':
              ccflags += [
                  '-m32',
                  #'-march=pentium4',
              ]
              if platform != 'haiku':
                  # NOTE: We need to ensure stack is realigned given that we
                  # produce shared objects, and have no control over the stack
                  # alignment policy of the application. Therefore we need
                  # -mstackrealign ore -mincoming-stack-boundary=2.
                  #
                  # XXX: We could have SSE without -mstackrealign if we always used
                  # __attribute__((force_align_arg_pointer)), but that's not
                  # always the case.
                  ccflags += [
                      '-mstackrealign', # ensure stack is aligned
                      '-msse', '-msse2', # enable SIMD intrinsics
                      '-mfpmath=sse', # generate SSE floating-point arithmetic
                  ]
              if platform in ['windows', 'darwin']:
                  # Workaround http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216
                  ccflags += ['-fno-common']
              if platform in ['haiku']:
                  # Make optimizations compatible with Pentium or higher on Haiku
                  ccflags += [
                      '-mstackrealign', # ensure stack is aligned
                      '-march=i586', # Haiku target is Pentium
                      '-mtune=i686' # use i686 where we can
                  ]
          if env['machine'] == 'x86_64':
              ccflags += ['-m64']
              if platform == 'darwin':
                  ccflags += ['-fno-common']
          if env['platform'] not in ('cygwin', 'haiku', 'windows'):
              ccflags += ['-fvisibility=hidden']
          # See also:
          # - http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
          ccflags += [
              '-Wall',
              '-Wno-long-long',
              '-fmessage-length=0', # be nice to Eclipse
          ]
          cflags += [
              '-Wmissing-prototypes',
              '-std=gnu99',
          ]
      if icc:
          cflags += [
              '-std=gnu99',
          ]
      if msvc:
          # See also:
          # - http://msdn.microsoft.com/en-us/library/19z1t1wy.aspx
          # - cl /?
          if env['build'] == 'debug':
              ccflags += [
                '/Od', # disable optimizations
                '/Oi', # enable intrinsic functions
              ]
          else:
              ccflags += [
                  '/O2', # optimize for speed
              ]
          if env['build'] in ('release', 'opt'):
              if not env['clang']:
                  ccflags += [
                      '/GL', # enable whole program optimization
                  ]
          else:
              ccflags += [
                  '/Oy-', # disable frame pointer omission
              ]
          ccflags += [
              '/W3', # warning level
              '/wd4018', # signed/unsigned mismatch
              '/wd4056', # overflow in floating-point constant arithmetic
              '/wd4244', # conversion from 'type1' to 'type2', possible loss of data
              '/wd4267', # 'var' : conversion from 'size_t' to 'type', possible loss of data
              '/wd4305', # truncation from 'type1' to 'type2'
              '/wd4351', # new behavior: elements of array 'array' will be default initialized
              '/wd4756', # overflow in constant arithmetic
              '/wd4800', # forcing value to bool 'true' or 'false' (performance warning)
              '/wd4996', # disable deprecated POSIX name warnings
          ]
          if env['clang']:
              ccflags += [
                  '-Wno-microsoft-enum-value', # enumerator value is not representable in underlying type 'int'
              ]
          if env['machine'] == 'x86':
              ccflags += [
                  '/arch:SSE2', # use the SSE2 instructions (default since MSVC 2012)
              ]
          if platform == 'windows':
              ccflags += [
                  # TODO
              ]
          # Automatic pdb generation
          # See http://scons.tigris.org/issues/show_bug.cgi?id=1656
          env.EnsureSConsVersion(0, 98, 0)
          env['PDB'] = '${TARGET.base}.pdb'
      env.Append(CCFLAGS = ccflags)
      env.Append(CFLAGS = cflags)
      env.Append(CXXFLAGS = cxxflags)
  
      if env['platform'] == 'windows' and msvc:
          # Choose the appropriate MSVC CRT
          # http://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx
          if env['build'] in ('debug', 'checked'):
              env.Append(CCFLAGS = ['/MTd'])
              env.Append(SHCCFLAGS = ['/LDd'])
          else:
              env.Append(CCFLAGS = ['/MT'])
              env.Append(SHCCFLAGS = ['/LD'])
      
      # Static code analysis
      if env['analyze']:
          if env['msvc']:
              # http://msdn.microsoft.com/en-us/library/ms173498.aspx
              env.Append(CCFLAGS = [
                  '/analyze',
                  #'/analyze:log', '${TARGET.base}.xml',
                  '/wd28251', # Inconsistent annotation for function
              ])
          if env['clang']:
              # scan-build will produce more comprehensive output
              env.Append(CCFLAGS = ['--analyze'])
  
      # https://github.com/google/sanitizers/wiki/AddressSanitizer
      if env['asan']:
          if gcc_compat:
              env.Append(CCFLAGS = [
                  '-fsanitize=address',
              ])
              env.Append(LINKFLAGS = [
                  '-fsanitize=address',
              ])
  
      # Assembler options
      if gcc_compat:
          if env['machine'] == 'x86':
              env.Append(ASFLAGS = ['-m32'])
          if env['machine'] == 'x86_64':
              env.Append(ASFLAGS = ['-m64'])
  
      # Linker options
      linkflags = []
      shlinkflags = []
      if gcc_compat:
          if env['machine'] == 'x86':
              linkflags += ['-m32']
          if env['machine'] == 'x86_64':
              linkflags += ['-m64']
          if env['platform'] not in ('darwin'):
              shlinkflags += [
                  '-Wl,-Bsymbolic',
              ]
          # Handle circular dependencies in the libraries
          if env['platform'] in ('darwin'):
              pass
          else:
              env['_LIBFLAGS'] = '-Wl,--start-group ' + env['_LIBFLAGS'] + ' -Wl,--end-group'
          if env['platform'] == 'windows':
              linkflags += [
                  '-Wl,--nxcompat', # DEP
                  '-Wl,--dynamicbase', # ASLR
              ]
              # Avoid depending on gcc runtime DLLs
              linkflags += ['-static-libgcc']
              if 'w64' in env['CC'].split('-'):
                  linkflags += ['-static-libstdc++']
              # Handle the @xx symbol munging of DLL exports
              shlinkflags += ['-Wl,--enable-stdcall-fixup']
              #shlinkflags += ['-Wl,--kill-at']
      if msvc:
          if env['build'] in ('release', 'opt') and not env['clang']:
              # enable Link-time Code Generation
              linkflags += ['/LTCG']
              env.Append(ARFLAGS = ['/LTCG'])
      if platform == 'windows' and msvc:
          # See also:
          # - http://msdn2.microsoft.com/en-us/library/y0zzbyt4.aspx
          linkflags += [
              '/fixed:no',
              '/incremental:no',
              '/dynamicbase', # ASLR
              '/nxcompat', # DEP
          ]
      env.Append(LINKFLAGS = linkflags)
      env.Append(SHLINKFLAGS = shlinkflags)
  
      # We have C++ in several libraries, so always link with the C++ compiler
      if gcc_compat:
          env['LINK'] = env['CXX']
  
      # Default libs
      libs = []
      if env['platform'] in ('darwin', 'freebsd', 'linux', 'posix', 'sunos'):
          libs += ['m', 'pthread', 'dl']
      if env['platform'] in ('linux',):
          libs += ['rt']
      if env['platform'] in ('haiku'):
          libs += ['root', 'be', 'network', 'translation']
      env.Append(LIBS = libs)
  
      # OpenMP
      if env['openmp']:
          if env['msvc']:
              env.Append(CCFLAGS = ['/openmp'])
              # When building openmp release VS2008 link.exe crashes with LNK1103 error.
              # Workaround: overwrite PDB flags with empty value as it isn't required anyways
              if env['build'] == 'release':
                  env['PDB'] = ''
          if env['gcc']:
              env.Append(CCFLAGS = ['-fopenmp'])
              env.Append(LIBS = ['gomp'])
  
      # Load tools
      env.Tool('lex')
      if env['msvc']:
          env.Append(LEXFLAGS = [
              # Force flex to use const keyword in prototypes, as relies on
              # __cplusplus or __STDC__ macro to determine whether it's safe to
              # use const keyword, but MSVC never defines __STDC__ unless we
              # disable all MSVC extensions.
              '-DYY_USE_CONST=',
          ])
          # Flex relies on __STDC_VERSION__>=199901L to decide when to include
          # C99 inttypes.h.  We always have inttypes.h available with MSVC
          # (either the one bundled with MSVC 2013, or the one we bundle
          # ourselves), but we can't just define __STDC_VERSION__ without
          # breaking stuff, as MSVC doesn't fully support C99.  There's also no
          # way to premptively include stdint.
          env.Append(CCFLAGS = ['-FIinttypes.h'])
      if host_platform.system() == 'Windows':
          # Prefer winflexbison binaries, as not only they are easier to install
          # (no additional dependencies), but also better Windows support.
          if check_prog(env, 'win_flex'):
              env["LEX"] = 'win_flex'
              env.Append(LEXFLAGS = [
                  # windows compatibility (uses <io.h> instead of <unistd.h> and
                  # _isatty, _fileno functions)
                  '--wincompat'
              ])
  
      env.Tool('yacc')
      if host_platform.system() == 'Windows':
          if check_prog(env, 'win_bison'):
              env["YACC"] = 'win_bison'
  
      if env['llvm']:
          env.Tool('llvm')
      
      # Custom builders and methods
      env.Tool('custom')
      env.AddMethod(install_program, 'InstallProgram')
      env.AddMethod(install_shared_library, 'InstallSharedLibrary')
      env.AddMethod(msvc2013_compat, 'MSVC2013Compat')
      env.AddMethod(unit_test, 'UnitTest')
  
      env.PkgCheckModules('X11', ['x11', 'xext', 'xdamage >= 1.1', 'xfixes', 'glproto >= 1.4.13', 'dri2proto >= 2.8'])
      env.PkgCheckModules('XCB', ['x11-xcb', 'xcb-glx >= 1.8.1', 'xcb-dri2 >= 1.8'])
      env.PkgCheckModules('XF86VIDMODE', ['xxf86vm'])
      env.PkgCheckModules('DRM', ['libdrm >= 2.4.75'])
  
      if env['x11']:
          env.Append(CPPPATH = env['X11_CPPPATH'])
  
      env['dri'] = env['x11'] and env['drm']
  
      # for debugging
      #print env.Dump()
  
  
  def exists(env):
      return 1