Fix support of posix_memalloc for Linux

[stweil]

posix_memalloc is only declared conditionally in stdlib.h,
so add one of the possible definitions to get the declaration.

Signed-off-by: Stefan Weil sw@weilnetz.de

[malaterre]

please set that only for minimal setup (only for posix_memalloc).

[stweil]

I'm not a cmake expert. How can I set that definition only for the posix_memalloc test?

[malaterre]

I would use unset when done

[stweil]

I updated the patch (and also fixed the commit message).

[stweil]

Patch updated because of commit 38ffbbe.

[mayeut]

@stweil,
This PR fails to build under linux & macos. c.f. http://my.cdash.org/index.php?project=OPENJPEG&date=2015-11-01

[stweil]

@mayeut: It should be fixed now. The failure only occurred when building thirdparty code, too.

[stweil]

Next iteration: Windows does not provide unistd.h.

[stweil]

Ping? I think this request can be pulled.

[mayeut]

@stweil seems that reverting the fix for tiff broke the build. Can you merge the new master branch in to check that all tests are OK ?

[stweil]

@mayeut, obviously the rebased patch passes all checks.

[malaterre]

That's really bad, the official reference is actually missing from http://pubs.opengroup.org/onlinepubs/009695399/functions/posix_memalign.html. Is the Linux implementation a bit too restrictive ?

[malaterre]

I am ready to merge thie PR until I understand the comment about feeko/ftello. We had a mechanism where _FILE_OFFSET_BITS == 64 was set. Isn't it the case anymore ?

[stweil]

fseeko, ftello have the same requirements as posix_memalign to get declared. In the current git master, the compiler complains about missing declarations for those functions. The patch fixes that problem, too.

[malaterre]

@stweil that is stlighty incorrect. fseeko/ftello are available as soon as you define _FILE_OFFSET_BITS == 64, hence my request for more comment on your side. Does your compiler requires _POSIX_C_SOURCE ?

[stweil]

On my 64 bit Debian GNU Linux, _FILE_OFFSET_BITS is not set (in src/lib/openjp2/opj_config_private.h). Therefore I get these compiler messages:

[  1%] Building C object src/lib/openjp2/CMakeFiles/openjp2.dir/openjpeg.c.o
/openjpeg/src/lib/openjp2/openjpeg.c: In function ‘opj_get_data_length_from_file’:
/openjpeg/src/lib/openjp2/openjpeg.c:101:2: warning: implicit declaration of function ‘fseeko’ [-Wimplicit-function-declaration]
  OPJ_FSEEK(p_file, 0, SEEK_END);
  ^
/openjpeg/src/lib/openjp2/openjpeg.c:102:2: warning: implicit declaration of function ‘ftello’ [-Wimplicit-function-declaration]
  file_length = (OPJ_OFF_T)OPJ_FTELL(p_file);
  ^

Extract from the man page of fseeko:

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   fseeko(), ftello():
       _FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600
       (defining the obsolete _LARGEFILE_SOURCE macro also works)

So defining one of _FILE_OFFSET_BITS, _POSIX_C_SOURCE or _XOPEN_SOURCE fixes the compiler warnings. Maybe _FILE_OFFSET_BITS is set on 32 bit Linux. Then the definition of _POSIX_C_SOURCE is not needed for fseeko, but it won't harm.

[detonin]

@stweil Thanks. Merged.