c3-lang/libffi

diff --git a/README b/README
index 7aee5b4..9cba257 100644
--- a/README
+++ b/README
@@ -146,12 +146,17 @@ It's also possible to build libffi on Windows platforms with
 Microsoft's Visual C++ compiler.  In this case, use the msvcc.sh
 wrapper script during configuration like so:
 
-path/to/configure CC=path/to/msvcc.sh CXX=path/to/msvcc.sh LD=link CPP=\"cl -nologo -EP\"
+path/to/configure CC=path/to/msvcc.sh CXX=path/to/msvcc.sh LD=link CPP="cl -nologo -EP"
 
 For 64-bit Windows builds, use CC="path/to/msvcc.sh -m64" and
 CXX="path/to/msvcc.sh -m64".  You may also need to specify --build
 appropriately.
 
+It is also possible to build libffi on Windows platforms with the LLVM
+project's clang-cl compiler, like below:
+
+path/to/configure CC="path/to/msvcc.sh -clang-cl" CXX="path/to/msvcc.sh -clang-cl" LD=link CPP="clang-cl -EP"
+
 When building with MSVC under a MingW environment, you may need to
 remove the line in configure that sets 'fix_srcfile_path' to a 'cygpath'
 command.  ('cygpath' is not present in MingW, and is not required when
diff --git a/include/ffi.h.in b/include/ffi.h.in
index 70c6179..ebed0aa 100644
--- a/include/ffi.h.in
+++ b/include/ffi.h.in
@@ -68,7 +68,7 @@ extern "C" {
 
 #ifndef LIBFFI_ASM
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(__clang__)
 #define __attribute__(X)
 #endif
 
diff --git a/msvcc.sh b/msvcc.sh
index 9208076..65fbfef 100755
--- a/msvcc.sh
+++ b/msvcc.sh
@@ -44,7 +44,8 @@
 
 args_orig=$@
 args="-nologo -W3"
-md=-MD
+static_crt=
+debug_crt=
 cl="cl"
 ml="ml"
 safeseh="-safeseh"
@@ -63,11 +64,15 @@ do
       shift 1
     ;;
     -m64)
-      cl="cl"   # "$MSVC/x86_amd64/cl"
       ml="ml64" # "$MSVC/x86_amd64/ml64"
       safeseh=
       shift 1
     ;;
+    -clang-cl)
+      cl="clang-cl"
+      safeseh=
+      shift 1
+    ;;
     -O0)
       args="$args -Od"
       shift 1
@@ -110,9 +115,14 @@ do
       defines="$defines $1"
       shift 1
     ;;
+    -DUSE_STATIC_RTL)
+      # Link against static CRT.
+      static_crt=1
+      shift 1
+    ;;
     -DUSE_DEBUG_RTL)
       # Link against debug CRT.
-      md=-MDd
+      debug_crt=1
       shift 1
     ;;
     -c)
@@ -207,6 +217,16 @@ if [ -n "$opt" ]; then
     args="$args -link -OPT:REF -OPT:ICF -INCREMENTAL:NO"
 fi
 
+if [ -n "$static_crt" ]; then
+    md=-MT
+else
+    md=-MD
+fi
+
+if [ -n "$debug_crt" ]; then
+    md="${md}d"
+fi
+
 if [ -n "$assembly" ]; then
     if [ -z "$outdir" ]; then
       outdir="."