Automatically create .dSYM for libcompiler_rt.dylib when using Apple's internal build system

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@168625 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/make/config.mk b/make/config.mk
index 12d8bc2..6398d05 100644
--- a/make/config.mk
+++ b/make/config.mk
@@ -21,6 +21,7 @@
 DATE := date
 LIPO := lipo
 CP := cp
+DSYMUTIL := dsymutil
 
 VERBOSE := 0
 DEBUGMAKE :=