Implement `silent' build rules. * automake.in (ccer): New field in the language structure. Initialize it for all registered languages. (verbose_var, verbose_flag, verbose_dispatch) (silent_flag, define_verbose_var, define_verbose_tagvar) (define_verbose_libtool): New functions. (handle_languages, handle_programs, handle_libraries) (handle_ltlibraries, handle_configure) (define_compiler_variable, define_linker_variable) (define_per_target_linker_variable): Use them where appropriate to define variables to implement the silent output machinery. * lib/Automake/Options.pm (_process_option_list): Accept `silent', turning off `portability-recursive'. * lib/am/depend2.am: Add %VERBOSE% and %SILENT% prefixes where appropriate. * lib/am/lex.am: Likewise. * lib/am/library.am: Likewise. * lib/am/ltlibrary.am: Likewise. * lib/am/program.am: Likewise. * lib/am/yacc.am: Likewise. * m4/init.m4 (AM_INIT_AUTOMAKE): Substitute, but do not define, AM_BACKSLASH. * tests/defs.in: Unset `V', to avoid influencing inner tests. Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>