Globally disable -fno-strict-aliasing, for reasons given in the comment.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105644 91177308-0d34-0410-b5e6-96231b3b80d8

Makefile

@@ -38,6 +38,16 @@ ifdef CLANG_VENDOR
 CPP.Flags += -DCLANG_VENDOR='"$(CLANG_VENDOR) "'
 endif
 
+# Disable -fstrict-aliasing. Darwin disables it by default (and LLVM doesn't
+# work with it enabled with GCC), Clang/llvm-gc don't support it yet, and newer
+# GCC's have false positive warnings with it on Linux (which prove a pain to
+# fix). For example:
+#   http://gcc.gnu.org/PR41874
+#   http://gcc.gnu.org/PR41838
+#
+# We can revisit this when LLVM/Clang support it.
+CXX.Flags += -fno-strict-aliasing
+
 ###
 # Clang Top Level specific stuff.