Add ability to set OPTIONS for compile

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@190371 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/buildit b/lib/buildit
index b18491d..5a4a710 100755
--- a/lib/buildit
+++ b/lib/buildit
@@ -82,12 +82,12 @@
 set -x
 
 for FILE in ../src/*.cpp; do
-	$CXX -c -g -O3 $RC_CFLAGS $EXTRA_FLAGS -I../include $FILE
+	$CXX -c -g -O3 $RC_CFLAGS $EXTRA_FLAGS -I../include $OPTIONS $FILE
 done
 case $TRIPLE in
   *-*-mingw*)
   for FILE in ../src/support/win32/*.cpp; do
-    $CXX -c -g -Os $RC_CFLAGS $EXTRA_FLAGS -I../include $FILE
+    $CXX -c -g -Os $RC_CFLAGS $EXTRA_FLAGS -I../include $OPTIONS $FILE
   done
   ;;
 esac