diff --git a/configure.ac b/configure.ac index a413ce57..2d1a7122 100644 --- a/configure.ac +++ b/configure.ac @@ -217,10 +217,7 @@ AC_C_VARARRAYS AC_CHECK_DEFINE([__wasi__], [WASI="yes"], []) -AC_CHECK_DEFINE([_FORTIFY_SOURCE], [], [ - AX_CHECK_COMPILE_FLAG([-D_FORTIFY_SOURCE=2], - [CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2"]) -]) +AX_ADD_FORTIFY_SOURCE AX_CHECK_COMPILE_FLAG([-fvisibility=hidden], [CFLAGS="$CFLAGS -fvisibility=hidden"]) diff --git a/m4/ax_add_fortify_source.m4 b/m4/ax_add_fortify_source.m4 new file mode 100644 index 00000000..b88d496f --- /dev/null +++ b/m4/ax_add_fortify_source.m4 @@ -0,0 +1,74 @@ +# =========================================================================== +# 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 or linker errors. Some distributions (such as +# Gentoo Linux) enable _FORTIFY_SOURCE globally in their compilers, +# leading to unnecessary warnings in the form of +# +# :0:0: error: "_FORTIFY_SOURCE" redefined [-Werror] +# : 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 +# Copyright (c) 2019 Reini Urban +# +# 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 3 + +AC_DEFUN([AX_ADD_FORTIFY_SOURCE],[ + 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 + int main() { + const char *s = " "; + strcpy(s, "x"); + return strlen(s)-1; + } + ]] + )], + [ + AC_MSG_RESULT([yes]) + CPPFLAGS="$CPPFLAGS -D_FORTIFY_SOURCE=2" + ], [ + AC_MSG_RESULT([no]) + ], + ), + [ + AC_MSG_RESULT([no]) + ]) +])