In simple-chrome, clang is a shell wrapper, it calls clang.elf, which is the
real binary, then, clang.elf calls clang.elf itself. It is the last invocation
"clang.elf -> clang.elf" that breaks, because direct calls to clang.elf misses
all environment setup in clang wrapper. Fix this by calling to clang wrapper
instead of clang.elf binary.

diff --git a/clang/tools/driver/driver.cpp b/clang/tools/driver/driver.cpp
index c3a3aab066ac..d1a4194a52f5 100644
--- a/clang/tools/driver/driver.cpp
+++ b/clang/tools/driver/driver.cpp
@@ -457,6 +457,9 @@ int main(int Argc, const char **Argv) {
   }
 
   std::string Path = GetExecutablePath(Args[0], CanonicalPrefixes);
+  size_t PathLen = Path.length();
+  if (PathLen > 4 && Path.substr(PathLen - 4) == ".elf")
+    Path = Path.substr(0, PathLen - 4);
 
   // Whether the cc1 tool should be called inside the current process, or if we
   // should spawn a new clang subprocess (old behavior).