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Check whether -D_FORTIFY_SOURCE=2 can be added to CPPFLAGS without macro redefinition warnings, other cpp warnings or linker. Some distributions (such as Ubuntu or 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- It broke -D_FORTIFY_SOURCE support, and would need -lssp or -fstack-protector. See Try to actually link it.

Source Code

Download the latest version of ax_add_fortify_source.m4 or browse the macro’s revision history.


Copyright © 2017 David Seifert
Copyright © 2019, 2023 Reini Urban

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