Use $CC instead of gcc in testsuite.
--- a/testsuite/Makefile.am
+++ b/testsuite/Makefile.am
@@ -39,6 +39,8 @@ env.exp: Makefile
 	rm -f env.exp
 	echo set libelf_LD_LIBRARY_PATH '"$(libelf_LD_LIBRARY_PATH)"' >> $@
 	echo set libunwind_LD_LIBRARY_PATH '"$(libunwind_LD_LIBRARY_PATH)"' >> $@
+	echo set CC_FOR_TARGET '"$(CC)"' >> $@
+	echo set CXX_FOR_TARGET '"$(CXX)"' >> $@
 
 CLEANFILES = *.o *.so *.log *.sum *.ltrace site.bak setval.tmp site.exp env.exp