Re: Autoconf does not like "-D_FORTIFY_SOURCE=2 -O2"

[Paul Eggert]

On 05/07/2013 08:49 PM, Anatol Pomozov wrote:

> Linux Arch distributive recently added following compilation flags to
> CPPFLAGS: "-D_FORTIFY_SOURCE=2 -O2". Unfortunately it breaks autoconf based
> projects such as gdb, gcc, ...
> 
> The issue is that autoconf compiles some programs to find whether system
> has headers. And to compile it uses only preprocessor defines from CPPFLAGS
> (-D_FORTIFY_SOURCE=2 in case of Arch). recent versions of glibc produces a
> warning when it compiles apps with _FORTIFY_SOURCE but without -O2.

Sorry, I don't understand.  If CPPFLAGS="-D_FORTIFY_SOURCE=2 -O2",
and if 'configure' uses preprocessor defines from CPPFLAGS,
then 'configure' should be using -D_FORTIFY_SOURCE=2 -O2.
But you seem to be implying that 'configure' is using -D_FORTIFY_SOURCE=2
without -O2.  How can this be?

> recent versions of glibc produces a
> warning when it compiles apps with _FORTIFY_SOURCE but without -O2

That's a real problem, which will break lots of things.
Fix that, and your Autoconf issue will go away.