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Diffstat (limited to 'm4/ax_add_fortify_source.m4')
| -rw-r--r-- | m4/ax_add_fortify_source.m4 | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/m4/ax_add_fortify_source.m4 b/m4/ax_add_fortify_source.m4 new file mode 100644 index 0000000..7e15312 --- /dev/null +++ b/m4/ax_add_fortify_source.m4 @@ -0,0 +1,80 @@ +# =========================================================================== +# https://www.gnu.org/software/autoconf-archive/ax_add_fortify_source.html +# =========================================================================== +# +# SYNOPSIS +# +# AX_ADD_FORTIFY_SOURCE +# +# DESCRIPTION +# +# Check whether -D_FORTIFY_SOURCE=2 can be added to CPPFLAGS without macro +# redefinition warnings, other cpp warnings or linker. Some distributions +# (such as Gentoo Linux) enable _FORTIFY_SOURCE globally in their +# compilers, leading to unnecessary warnings in the form of +# +# <command-line>:0:0: error: "_FORTIFY_SOURCE" redefined [-Werror] +# <built-in>: note: this is the location of the previous definition +# +# which is a problem if -Werror is enabled. This macro checks whether +# _FORTIFY_SOURCE is already defined, and if not, adds -D_FORTIFY_SOURCE=2 +# to CPPFLAGS. +# +# Newer mingw-w64 msys2 package comes with a bug in +# headers-git-7.0.0.5546.d200317d-1. It broke -D_FORTIFY_SOURCE support, +# and would need -lssp or -fstack-protector. See +# https://github.com/msys2/MINGW-packages/issues/5803. Try to actually +# link it. +# +# LICENSE +# +# Copyright (c) 2017 David Seifert <soap@gentoo.org> +# Copyright (c) 2019 Reini Urban <rurban@cpan.org> +# +# Copying and distribution of this file, with or without modification, are +# permitted in any medium without royalty provided the copyright notice +# and this notice are preserved. This file is offered as-is, without any +# warranty. + +#serial 4 + +AC_DEFUN([AX_ADD_FORTIFY_SOURCE],[ + ac_save_cflags=$CFLAGS + ac_cwerror_flag=yes + AX_CHECK_COMPILE_FLAG([-Werror],[CFLAGS="$CFLAGS -Werror"]) + AC_MSG_CHECKING([whether to add -D_FORTIFY_SOURCE=2 to CPPFLAGS]) + AC_LINK_IFELSE([ + AC_LANG_PROGRAM([], + [[ + #ifndef _FORTIFY_SOURCE + return 0; + #else + this_is_an_error; + #endif + ]] + )], + AC_LINK_IFELSE([ + AC_LANG_SOURCE([[ + #define _FORTIFY_SOURCE 2 + #include <string.h> + int main() { + char *s = " "; + strcpy(s, "x"); + return strlen(s)-1; + } + ]] + )], + [ + AC_MSG_RESULT([yes]) + CFLAGS=$ac_save_cflags + CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2" + ], [ + AC_MSG_RESULT([no]) + CFLAGS=$ac_save_cflags + ], + ), + [ + AC_MSG_RESULT([no]) + CFLAGS=$ac_save_cflags + ]) +]) |