build all C++ files in compiler-rt with -fno-exceptions

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@145967 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/make/config.mk b/make/config.mk
index bddc6f8..5656ad6 100644
--- a/make/config.mk
+++ b/make/config.mk
@@ -39,3 +39,7 @@
 ifndef Summary
   Summary = $(Echo)
 endif
+
+###
+# Common compiler options
+COMMON_CXXFLAGS=-fno-exceptions