Add header search path for Gentoo stable, x86_64 version.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74626 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/InitHeaderSearch.cpp b/lib/Frontend/InitHeaderSearch.cpp
index 7a2b3a7..8c80786 100644
--- a/lib/Frontend/InitHeaderSearch.cpp
+++ b/lib/Frontend/InitHeaderSearch.cpp
@@ -178,6 +178,14 @@
     AddPath("/usr/lib/gcc/i686-pc-linux-gnu/4.1.2/include/g++-v4/backward",
             System, true, false, false);
 
+    // Gentoo amd64 stable
+    AddPath("/usr/lib/gcc/x86_64-pc-linux-gnu/4.1.2/include/g++-v4", System,
+            true, false, false);
+    AddPath("/usr/lib/gcc/x86_64-pc-linux-gnu/4.1.2/include/g++-v4/"
+            "i686-pc-linux-gnu", System, true, false, false);
+    AddPath("/usr/lib/gcc/x86_64-pc-linux-gnu/4.1.2/include/g++-v4/backward",
+            System, true, false, false);
+
     // DragonFly
     AddPath("/usr/include/c++/4.1", System, true, false, false);