Allow to build with mingw-clang (#579)

For some reason, compiling sysv.S with mingw-clang fails with:
```
error: invalid variant 'ffi_closure_inner@8'
```

This can be fixed (worked around?) by quoting the symbol. This works
fine with mingw-gcc too.

diff --git a/src/x86/sysv.S b/src/x86/sysv.S
index 6d5648332cb617295ec752a418d3f80521aac174..d8ab4b02642a57d55da3596822366f070b942653 100644 (file)
--- a/src/x86/sysv.S
+++ b/src/x86/sysv.S
@@ -56,8 +56,8 @@
 
 /* Handle win32 fastcall name mangling.  */
 #ifdef X86_WIN32
-# define ffi_call_i386         @ffi_call_i386@8
-# define ffi_closure_inner     @ffi_closure_inner@8
+# define ffi_call_i386         "@ffi_call_i386@8"
+# define ffi_closure_inner     "@ffi_closure_inner@8"
 #else
 # define ffi_call_i386         C(ffi_call_i386)
 # define ffi_closure_inner     C(ffi_closure_inner)