Use the correct compiler to compute dependencies.

This uses $(CXX) instead of $(CC) to generate the .d files for tests built
with Makefiles.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@187426 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/make/Makefile.rules b/test/make/Makefile.rules
index d4a9145..e1d1229 100644
--- a/test/make/Makefile.rules
+++ b/test/make/Makefile.rules
@@ -326,7 +326,7 @@
 
 %.d: %.cpp
 	@set -e; rm -f $@; \
-	$(CC) -M $(CXXFLAGS) $< > $@.$$$$; \
+	$(CXX) -M $(CXXFLAGS) $< > $@.$$$$; \
 	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
 	rm -f $@.$$$$
 
@@ -338,7 +338,7 @@
 
 %.d: %.mm
 	@set -e; rm -f $@; \
-	$(CC) -M $(CXXFLAGS) $< > $@.$$$$; \
+	$(CXX) -M $(CXXFLAGS) $< > $@.$$$$; \
 	sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
 	rm -f $@.$$$$