[libclang] Check for environment variable CINDEXTEST_NOTHREADS in clang_reparseTranslationUnit.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143242 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index a9fd9e5..8f0c225 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -2718,6 +2718,12 @@
                                  unsigned options) {
   ReparseTranslationUnitInfo RTUI = { TU, num_unsaved_files, unsaved_files,
                                       options, 0 };
+
+  if (getenv("CINDEXTEST_NOTHREADS")) {
+    clang_reparseTranslationUnit_Impl(&RTUI);
+    return RTUI.result;
+  }
+
   llvm::CrashRecoveryContext CRC;
 
   if (!RunSafely(CRC, clang_reparseTranslationUnit_Impl, &RTUI)) {