bpo-32390: Modify syntax to satisify xlC/gcc compiler requirements on AIX: assignment between types "unsigned long" and "struct fsid_t" is not allowed

[aixtools]

Error message was: "./Modules/posixmodule.c", line 9328.64: 1506-280 (S) Function argument assignment between types "unsigned long" and "struct fsid_t" is not allowed.

https://bugs.python.org/issue32390

[aixtools]

Seems 'clang' and AIX xlc and gcc are not agreeing:

• The clang test (of ontinuous-integration/travis-ci/pr) fails with:

./Modules/posixmodule.c:9328:71: error: member reference base type 'unsigned long' is not a structure or union
    PyStructSequence_SET_ITEM(v, 10, PyLong_FromUnsignedLong(st.f_fsid.val[0]));
                                                             ~~~~~~~~~^~~~
./Include/structseq.h:38:69: note: expanded from macro 'PyStructSequence_SET_ITEM'
#define PyStructSequence_SET_ITEM(op, i, v) PyTuple_SET_ITEM(op, i, v)
                                                                    ^
./Include/tupleobject.h:62:75: note: expanded from macro 'PyTuple_SET_ITEM'
#define PyTuple_SET_ITEM(op, i, v) (((PyTupleObject *)(op))->ob_item[i] = v)
                                                                          ^

• While the AIX buildbot (e.g., http://buildbot.python.org/all/#/builders/10/builds/417)
  fails with:

gcc -pthread -Wno-unused-result -Wsign-compare -g -Og -Wall -Wstrict-prototypes    -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration   -I. -I./Include    -DPy_BUILD_CORE  -c ./Modules/posixmodule.c -o Modules/posixmodule.o
In file included from ./Include/Python.h:85:0,
                 from ./Modules/posixmodule.c:27:
./Modules/posixmodule.c: In function '_pystatvfs_fromstructstatvfs':
./Modules/posixmodule.c:9328:62: error: incompatible type for argument 1 of 'PyLong_FromUnsignedLong'
     PyStructSequence_SET_ITEM(v, 10, PyLong_FromUnsignedLong(st.f_fsid));
                                                              ^
./Include/tupleobject.h:62:75: note: in definition of macro 'PyTuple_SET_ITEM'
 #define PyTuple_SET_ITEM(op, i, v) (((PyTupleObject *)(op))->ob_item[i] = v)
                                                                           ^
./Modules/posixmodule.c:9328:5: note: in expansion of macro 'PyStructSequence_SET_ITEM'
     PyStructSequence_SET_ITEM(v, 10, PyLong_FromUnsignedLong(st.f_fsid));
     ^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./Include/Python.h:78:0,
                 from ./Modules/posixmodule.c:27:
./Include/longobject.h:19:24: note: expected 'long unsigned int' but argument is of type 'fsid_t {aka struct fsid_t}'
 PyAPI_FUNC(PyObject *) PyLong_FromUnsignedLong(unsigned long);
                        ^~~~~~~~~~~~~~~~~~~~~~~
Makefile:1765: recipe for target 'Modules/posixmodule.o' failed

• I'll modify the change (to put it behind _AIX) - as AIX seems to be having an issue regardless of gcc or xlc (which is how I spotted the issue originally).
• See if that passes tests - and then I welcome your input for a potentially prettier solution!

[xdegaye]

I would prefer:

Fix os.statvfs(path) on AIX where the f_fsid member of the statvfs structure is a structure instead of unsigned long. Patch by Michael Felt.

[aixtools]

I did more research and found a way for typedefs to be the same. Added comments in code and summary in News.

If this is not the way you want it documented, please reply.

[xdegaye]

A comment in a source file with part of a AIX header being copy-pasted in it is not correct, this should be done in the issue instead.

Please start a discussion in the issue.

[aixtools]

would like to emphasize, since 96a5e50 AIX cannot compile. This allows compile to continue.

p.s. title should be changed, as the syntax is now the same. The "default" action of defining _ALL_SOURCE is undone is closer to the truth.