_FORTIFY_SOURCE redefined while compiling on Gentoo with Portage

[RedL0tus]

It's a problem with compiling.

Please answer the following questions:

• Operating system and version: Gentoo Base System release 2.6
• How did you install fwupd (ex: from source, pacman, apt-get, etc): Portage
• Have you tried rebooting? No. It's a problem with compiling.
• Are you using an NVMe disk? Yes.
• Is secure boot enabled (only for the UEFI plugin)? No.

The compiling failed on Gentoo at:

[166/184] gcc -c ../fwupd-1.1.0/plugins/uefi/efi/fwupdate.c -o plugins/uefi/efi/fwupdate.o -Og -g3 -Wp,-D_FORTIFY_SOURCE=2 --param=ssp-buffer-size=4 -fexceptions -Wall -Werror -Wextra -std=gnu11 -fpic -fshort-wchar -ffreestanding -fno-strict-aliasing -fno-stack-protector -
fno-stack-check -fno-merge-constants -Wsign-compare -Wno-missing-field-initializers -grecord-gcc-switches '-DDEBUGDIR="/usr/lib64/debug"' -isystem /usr/include/efi -isystem /usr/include/efi/x86_64 -mno-red-zone -mno-sse -mno-mmx -DEFI_FUNCTION_WRAPPER -DGNU_EFI_USE_MS_ABI
FAILED: plugins/uefi/efi/fwupdate.o 
gcc -c ../fwupd-1.1.0/plugins/uefi/efi/fwupdate.c -o plugins/uefi/efi/fwupdate.o -Og -g3 -Wp,-D_FORTIFY_SOURCE=2 --param=ssp-buffer-size=4 -fexceptions -Wall -Werror -Wextra -std=gnu11 -fpic -fshort-wchar -ffreestanding -fno-strict-aliasing -fno-stack-protector -fno-stack-
check -fno-merge-constants -Wsign-compare -Wno-missing-field-initializers -grecord-gcc-switches '-DDEBUGDIR="/usr/lib64/debug"' -isystem /usr/include/efi -isystem /usr/include/efi/x86_64 -mno-red-zone -mno-sse -mno-mmx -DEFI_FUNCTION_WRAPPER -DGNU_EFI_USE_MS_ABI
<command-line>: error: "_FORTIFY_SOURCE" redefined [-Werror]
<built-in>: note: this is the location of the previous definition
cc1: all warnings being treated as errors

The problem seems to be Gentoo's GCC has built-in parameter that sets -D_FORTIFY_SOURCE to another value, and the build system set that value again.

My solution is to add -U_FORTIFY_SOURCE before -D_FORTIFY_SOURCE=2.
I believe there will be better solution so I opened this issue.

Link to Gentoo Bugzilla: https://bugs.gentoo.org/661068

[hughsie]

I guess it is slightly odd to unconditionally set _FORTIFY_SOURCE -- @superm1 any ideas here? My gut instinct is just to remove it from the meson.build file.

[superm1]

compiler.has_flags maybe? If that doesn't work then yeah I agree remove it.

[hughsie]

compiler.has_flags maybe

I don't think that'll work; it's not really a flag it's just a #define. I'll remove it.