Fix executable stack directive on Linux.
Summary: Use __linux__  to check for Linux and bring back the check for __GNU__.
Reviewers: echristo, krytarowski, compnerd, rengolin
Subscribers: phosek, llvm-commits, srhines
#endif
#define CONST_SECTION .section .rodata
-#if defined(__GNUC__) || defined(__ANDROID__) || defined(__FreeBSD__)
+#if defined(__GNU__) || defined(__FreeBSD__) || defined(__Fuchsia__) || \
+ defined(__linux__)
#define NO_EXEC_STACK_DIRECTIVE .section .note.GNU-stack,"",%progbits
#else
#define NO_EXEC_STACK_DIRECTIVE
