[Bug build/15414] Build fails with mingw32-w64 GCC-4.8.0

["freddie_chopin at op dot pl" <sourceware-bugzilla@sourceware.org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=15414

--- Comment #2 from Freddie Chopin <freddie_chopin at op dot pl> 2013-04-29 14:45:50 UTC ---
(In reply to comment #1)
> According to the GCC documentation, -Wall implies -Wformat.
> So offhand I would say it is a GCC bug.
> However, it seems like a reasonably simple workaround would
> be to add -Wformat to build_warnings in gdb/configure.ac.

But there's an EXPLICIT -Wno-format and the GDB changelog says it's there
because with mingw32 there may be some false positives for -Wformat. But these
two options conflict with each other - one saying to check for non-literal
strings (-Wformat-nonliteral), other saying to not check at all (-Wno-format).
Previously GCC probably ignored that silently, now it gives a warning, which
triggers an error because of -Werror. I don't think there's a bug, this
behavior makes perfect sense - GCC cannot do what you ask it to do, so it gives
you a warning.

I also have GCC 4.7.3 (mingw32) and there's the same behavior:

> gcc test.c -Wno-format -Wformat-nonliteral -Werror
cc1.exe: error: -Wformat-nonliteral ignored without -Wformat
[-Werror=format-non
literal]
cc1.exe: all warnings being treated as errors

> gcc --version
gcc (rev0, Built by MinGW-builds project) 4.7.3
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

>

If there's still need to disable these checks for mingw32 it has to be done
completely, so instead of just adding -Wno-format, -Wformat-nonliteral must be
reversed to -Wno-format-nonliteral. In that case there's no error:

> gcc test.c -Wno-format -Wno-format-nonliteral -Werror

>

test.c is just an empty main().

Previous - successful - compilations were done with GCC 4.7.2.

-- 
Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.