MinGW Build Error: _XOPEN_SOURCE in mxit

[Andrew Victor]

hi,

I've pushed a patch to fix this into release-2.x.y and default.




On 25 March 2015 at 16:15, Diego Nieto Cid <dnietoc at gmail.com> wrote:
> Hi Andrew
>
> I add you to a discussion about a mxit change in libpurple which is causing
> some trouble to compile the source under MinGW's latest version of gcc.
>
> El mié., 25 de marzo de 2015 a las 1:25, Jorge Villaseñor
> (<salinasv at gmail.com>) escribió:
>>
>> On Mon, Mar 2, 2015 at 2:57 PM, Diego Nieto Cid <dnietoc at gmail.com> wrote:
>>>
>>> Hi
>>>
>>> I'm working on a plugin (pidgin-gntp) for windows and I followed the
>>> instructions listed in the BuildingWinPidgin wiki page.
>>>
>>> However, when installing MinGW I used their setup tool which downloaded
>>> the latest GCC package, version 4.8.1.
>
>
> I finally used the recommended version (4.7.2) because the plugin was
> crashing pidgin on exit.
>
> Apparently, it was a problem in the stack smashing protection library
> (libssp) used by GCC which was incompatible with the one pidgin linked to.
>
>>>
>>>
>>> During the compilation of libpurple/protocols/mxit/profile.c, I am
>>> getting an error related to the preprocessor macro _XOPEN_SOURCE.
>>>
>>> Apparently, MinGW header files expect it, if defined, to be a number and
>>> the macro is used in comparisons, as it is showed in the build log below.
>>>
>>> Revision 21baa608701d [1] introduced the definition of _XOPEN_SOURCE in
>>> the profile.c compilation unit. However, it is defined as an empty value
>>> leading to errors in system headers.
>>>
>>> There are several conformance levels that can be requested by defining
>>> _XOPEN_SOURCE, as described in the relevant man page [2].
>>>
>>> As a quick fix, I'm going to define it to the lowest level. But I wanted
>>> to check with you what was intended by defining that macro.
>
>
> Using the lowest level worked just fine. So, with the definition
>
>     #define _XOPEN_SOURCE 1
>
> pidgin compiled correctly.
>
>>>
>>>
>>> If it is not clear what was intended, anybody knows what MinGW assumed in
>>> prior versions?
>
>
> After installing version 4.7.2, I can confirm that MinGW did not check the
> value of that macro. It only tested whether it was defined or not.
>
>>>
>>>
>>> Thanks!
>>>
>>> --
>>> [1] https://hg.pidgin.im/pidgin/main/rev/21baa608701d
>>> [2] http://man.he.net/man7/feature_test_macros
>>>
>>> Extract of the build log:
>>>
>>> make[3]: Entering directory
>>> `/src/pidgin/src-2.10.11/libpurple/protocols/mxit'
>>> gcc.exe -O2 -Wall -Waggregate-return -Wcast-align
>>> -Wdeclaration-after-statement -Werror-implicit-function-declaration -Wextra
>>> -Wno-sign-compare -Wno-unused-parameter -Winit-self -Wmissing-declarations
>>> -Wmissing-prototypes -Wnested-externs -Wpointer-arith -Wundef
>>> -Wstack-protector -fwrapv -fno-strict-overflow
>>> -Wno-missing-field-initializers -Wformat-security -fstack-protector-all
>>> --param ssp-buffer-size=1 -pipe -mms-bitfields -g -DHAVE_CYRUS_SASL
>>> -DHAVE_CONFIG_H -DWIN32_LEAN_AND_MEAN -I.
>>> -I../../../../win32-dev/gtk_2_0-2.14/include
>>> -I../../../../win32-dev/gtk_2_0-2.14/include/glib-2.0
>>> -I../../../../win32-dev/gtk_2_0-2.14/lib/glib-2.0/include
>>> -I../../../libpurple -I../../../libpurple/win32 -I../../.. -o profile.o -c
>>> profile.c
>>> In file included from
>>> d:\diego\programacion\mingw-0.6.2\include\time.h:15:0,
>>>                  from profile.c:27:
>>> d:\diego\programacion\mingw-0.6.2\include\_mingw.h:396:21: error:
>>> operator '<' has no left operand
>>>  #  if _XOPEN_SOURCE < 500
>>>                      ^
>>> d:\diego\programacion\mingw-0.6.2\include\_mingw.h:399:23: error:
>>> operator '<' has no left operand
>>>  #  elif _XOPEN_SOURCE < 600
>>>                        ^
>>> d:\diego\programacion\mingw-0.6.2\include\_mingw.h:402:23: error:
>>> operator '<' has no left operand
>>>  #  elif _XOPEN_SOURCE < 700
>>>                        ^
>>> make[3]: *** [profile.o] Error 1
>>
>>
>> This looks like a mxit change. I am not sure they Andrew monitors this
>> mailing list. I think you may have better luck if you address the mxit
>> development forums or him directly.
>
>
> Thanks Jorge, I added Andrew to the discussion.
>
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