For Linux/gnu compatibility, preinclude <stdc-predef.h> if the file is available

As reported in llvm bugzilla 32377.
Here’s a patch to add preinclude of stdc-predef.h.

The gcc documentation says “On GNU/Linux, <stdc-predef.h> is pre-included.” 
See https://gcc.gnu.org/gcc-4.8/porting_to.html;

The preinclude is inhibited with –ffreestanding.

Basically I fixed the failing test cases by adding –ffreestanding which inhibits
this behavior.

I fixed all the failing tests, including some in extra/test, there's a separate
patch for that which is linked here

Patch By: mibintc

Differential Revision: https://reviews.llvm.org/D34158

llvm-svn: 318669

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 384124bee2b..748c7ffbcdf 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2594,6 +2594,10 @@ static void ParsePreprocessorArgs(PreprocessorOptions &Opts, ArgList &Args,
   for (const Arg *A : Args.filtered(OPT_chain_include))
     Opts.ChainedIncludes.emplace_back(A->getValue());
 
+  // Add the ordered list of -fsystem-include-if-exists.
+  for (const Arg *A : Args.filtered(OPT_fsystem_include_if_exists))
+    Opts.FSystemIncludeIfExists.emplace_back(A->getValue());
+
   for (const Arg *A : Args.filtered(OPT_remap_file)) {
     std::pair<StringRef, StringRef> Split = StringRef(A->getValue()).split(';');