Initial commit of compatibility patch

Applying the patch is not yet automated.

Author: joshkel

.gitignore

@@ -2,4 +2,5 @@ build/
 downloads/
 env/
 llvm/
+llvm.orig/
 **/__pycache__/

patches/llvm-3.9.1.patch

@@ -0,0 +1,70 @@
+diff -ur llvm.orig/include/llvm/Analysis/TargetLibraryInfo.h llvm/include/llvm/Analysis/TargetLibraryInfo.h
+--- llvm.orig/include/llvm/Analysis/TargetLibraryInfo.h	2016-07-13 15:09:16.000000000 -0400
++++ llvm/include/llvm/Analysis/TargetLibraryInfo.h	2017-02-18 14:35:19.172195900 -0500
+@@ -18,6 +18,19 @@
+ #include "llvm/IR/PassManager.h"
+ #include "llvm/Pass.h"
+ 
++// Emscripten handles large file support by providing #defines from 64-bit
++// versions to 32-bit versions, but that breaks LLVM's use of those functions
++// as distinct symbols
++#ifdef __EMSCRIPTEN__
++#undef fopen64
++#undef fseeko64
++#undef fstat64
++#undef ftello64
++#undef lstat64
++#undef stat64
++#undef tmpfile64
++#endif
++
+ namespace llvm {
+ template <typename T> class ArrayRef;
+ 
+diff -ur llvm.orig/tools/clang/include/clang/Basic/LangOptions.h llvm/tools/clang/include/clang/Basic/LangOptions.h
+--- llvm.orig/tools/clang/include/clang/Basic/LangOptions.h	2016-05-18 05:06:38.000000000 -0400
++++ llvm/tools/clang/include/clang/Basic/LangOptions.h	2017-02-18 10:31:12.868636900 -0500
+@@ -29,8 +29,15 @@
+ /// this large collection of bitfields is a trivial class type.
+ class LangOptionsBase {
+ public:
++  // Large bitfields cause problems for Emscripten.
++  // See https://github.com/kripken/emscripten/issues/4540
++  // As a workaround, use less efficient non-bitfield representations.
++  typedef uint8_t OptWith1Bit;
++  typedef uint8_t OptWith2Bit;
++  typedef uint32_t OptWith32Bit;
++
+   // Define simple language options (with no accessors).
+-#define LANGOPT(Name, Bits, Default, Description) unsigned Name : Bits;
++#define LANGOPT(Name, Bits, Default, Description) OptWith ## Bits ## Bit Name;
+ #define ENUM_LANGOPT(Name, Type, Bits, Default, Description)
+ #include "clang/Basic/LangOptions.def"
+ 
+diff -ur llvm.orig/tools/clang/include/clang/Basic/VersionTuple.h llvm/tools/clang/include/clang/Basic/VersionTuple.h
+--- llvm.orig/tools/clang/include/clang/Basic/VersionTuple.h	2016-07-11 16:00:48.000000000 -0400
++++ llvm/tools/clang/include/clang/Basic/VersionTuple.h	2017-02-18 12:02:36.792630200 -0500
+@@ -31,6 +31,9 @@
+   unsigned Minor : 31;
+   unsigned HasMinor : 1;
+ 
++  // See https://github.com/kripken/emscripten/issues/4540
++  unsigned char :0;
++
+   unsigned Subminor : 31;
+   unsigned HasSubminor : 1;
+ 
+diff -ur llvm.orig/tools/clang/tools/c-index-test/CMakeLists.txt llvm/tools/clang/tools/c-index-test/CMakeLists.txt
+--- llvm.orig/tools/clang/tools/c-index-test/CMakeLists.txt	2016-02-20 15:34:55.000000000 -0500
++++ llvm/tools/clang/tools/c-index-test/CMakeLists.txt	2017-02-18 14:18:33.390434200 -0500
+@@ -1,6 +1,7 @@
+-set(LLVM_LINK_COMPONENTS
+-  support
+-)
++# Omit for Emscripten - it's included in libclang below.
++# set(LLVM_LINK_COMPONENTS
++#   support
++# )
+ 
+ add_clang_executable(c-index-test
+   c-index-test.c