[newlib-cygwin] newlib: ignore _FORTIFY_SOURCE when building newlib

[newlib-cygwin] newlib: ignore _FORTIFY_SOURCE when building newlib

[Michael Frysinger]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=df5de02e0ebc8627683bc50aeb68d0d2b0806f09

commit df5de02e0ebc8627683bc50aeb68d0d2b0806f09
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Mon Nov 8 21:42:12 2021 -0500

    newlib: ignore _FORTIFY_SOURCE when building newlib
    
    Some distros enable _FORTIFY_SOURCE by default which upsets building
    newlib which itself implements the logic for this define.  For example,
    building gets.c fails because the includes set up a gets() macro which
    expands in the definition.
    
    Since newlib isn't prepared to build itself with _FORTIFY_SOURCE, and
    it's not clear if it's even useful, ignore it when building the code.
    This also matches what glibc is doing.

Diff:
---
 newlib/libc/include/sys/features.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/newlib/libc/include/sys/features.h b/newlib/libc/include/sys/features.h
index 218807178..6b4999e83 100644
--- a/newlib/libc/include/sys/features.h
+++ b/newlib/libc/include/sys/features.h
@@ -320,7 +320,8 @@ extern "C" {
 #endif
 
 #if _FORTIFY_SOURCE > 0 && !defined(__cplusplus) && !defined(__lint__) && \
-   (__OPTIMIZE__ > 0 || defined(__clang__)) && __GNUC_PREREQ__(4, 1)
+   (__OPTIMIZE__ > 0 || defined(__clang__)) && __GNUC_PREREQ__(4, 1) && \
+   !defined(_COMPILING_NEWLIB)
 #  if _FORTIFY_SOURCE > 1
 #    define __SSP_FORTIFY_LEVEL 2
 #  else