Fix TestRegisterVariables for linux arm/arm64 gcc ver > 5

We are going to turn off buffer overflow introduced by gcc by turning off
FORTIFY_SOURCE.

Differential revision: https://reviews.llvm.org/D28666

llvm-svn: 291949

lldb/packages/Python/lldbsuite/test/lang/c/register_variables/Makefile

@@ -2,6 +2,6 @@ LEVEL = ../../../make
 
 C_SOURCES := test.c
 
-CFLAGS_EXTRAS += -O1
+CFLAGS_EXTRAS += -O1 -D_FORTIFY_SOURCE=0
 
 include $(LEVEL)/Makefile.rules