This patch converts a few more function definitions in glibc from
old-style K&R to prototype style. This is sufficient to build and
test on x86_64 and x86 with -Wold-style-definition (I'll test on some
more architectures before proposing the actual addition of
-Wold-style-definition).
Tested for x86_64 and x86 with -Wold-style-definition in use
(testsuite - this patch affects files containing assertions).
* io/fts.c (fts_open): Convert to prototype-style function
definition.
* malloc/mcheck.c (mcheck): Likewise.
(mcheck_pedantic): Likewise.
* posix/regexec.c (re_search_2_stub): Likewise. Use
internal_function.
(re_search_internal): Likewise.
* resolv/res_init.c [RESOLVSORT] (net_mask): Convert to
prototype-style function definition.
* sunrpc/clnt_udp.c (clntudp_call): Likewise.
* sunrpc/pmap_rmt.c (clnt_broadcast): Likewise.
* sunrpc/rpcsvc/rusers.x (xdr_utmp): Likewise.
(xdr_utmpptr): Likewise.
(xdr_utmparr): Likewise.
(xdr_utmpidle): Likewise.
(xdr_utmpidleptr): Likewise.
(xdr_utmpidlearr): Likewise.
This mostly automatically-generated patch converts 113 function
definitions in glibc from old-style K&R to prototype-style. Following
my other recent such patches, this one deals with the case of function
definitions in files that either contain assertions or where grep
suggested they might contain assertions - and thus where it isn't
possible to use a simple object code comparison as a sanity check on
the correctness of the patch, because line numbers are changed.
A few such automatically-generated changes needed to be supplemented
by manual changes for the result to compile. openat64 had a prototype
declaration with "..." but an old-style definition in
sysdeps/unix/sysv/linux/dl-openat64.c, and "..." needed adding to the
generated prototype in the definition (I've filed
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68024> for diagnosing
such cases in GCC; the old state was undefined behavior not requiring
a diagnostic, but one seems a good idea). In addition, as Florian has
noted regparm attribute mismatches between declaration and definition
are only diagnosed for prototype definitions, and five functions
needed internal_function added to their definitions (in the case of
__pthread_mutex_cond_lock, via the macro definition of
__pthread_mutex_lock) to compile on i386.
After this patch is in, remaining old-style definitions are probably
most readily fixed manually before we can turn on
-Wold-style-definition for all builds.
Tested for x86_64 and x86 (testsuite).
* crypt/md5-crypt.c (__md5_crypt_r): Convert to prototype-style
function definition.
* crypt/sha256-crypt.c (__sha256_crypt_r): Likewise.
* crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.
* debug/backtracesyms.c (__backtrace_symbols): Likewise.
* elf/dl-minimal.c (_itoa): Likewise.
* hurd/hurdmalloc.c (malloc): Likewise.
(free): Likewise.
(realloc): Likewise.
* inet/inet6_option.c (inet6_option_space): Likewise.
(inet6_option_init): Likewise.
(inet6_option_append): Likewise.
(inet6_option_alloc): Likewise.
(inet6_option_next): Likewise.
(inet6_option_find): Likewise.
* io/ftw.c (FTW_NAME): Likewise.
(NFTW_NAME): Likewise.
(NFTW_NEW_NAME): Likewise.
(NFTW_OLD_NAME): Likewise.
* libio/iofwide.c (_IO_fwide): Likewise.
* libio/strops.c (_IO_str_init_static_internal): Likewise.
(_IO_str_init_static): Likewise.
(_IO_str_init_readonly): Likewise.
(_IO_str_overflow): Likewise.
(_IO_str_underflow): Likewise.
(_IO_str_count): Likewise.
(_IO_str_seekoff): Likewise.
(_IO_str_pbackfail): Likewise.
(_IO_str_finish): Likewise.
* libio/wstrops.c (_IO_wstr_init_static): Likewise.
(_IO_wstr_overflow): Likewise.
(_IO_wstr_underflow): Likewise.
(_IO_wstr_count): Likewise.
(_IO_wstr_seekoff): Likewise.
(_IO_wstr_pbackfail): Likewise.
(_IO_wstr_finish): Likewise.
* locale/programs/localedef.c (normalize_codeset): Likewise.
* locale/programs/locarchive.c (add_locale_to_archive): Likewise.
(add_locales_to_archive): Likewise.
(delete_locales_from_archive): Likewise.
* malloc/malloc.c (__libc_mallinfo): Likewise.
* math/gen-auto-libm-tests.c (init_fp_formats): Likewise.
* misc/tsearch.c (__tfind): Likewise.
* nptl/pthread_attr_destroy.c (__pthread_attr_destroy): Likewise.
* nptl/pthread_attr_getdetachstate.c
(__pthread_attr_getdetachstate): Likewise.
* nptl/pthread_attr_getguardsize.c (pthread_attr_getguardsize):
Likewise.
* nptl/pthread_attr_getinheritsched.c
(__pthread_attr_getinheritsched): Likewise.
* nptl/pthread_attr_getschedparam.c
(__pthread_attr_getschedparam): Likewise.
* nptl/pthread_attr_getschedpolicy.c
(__pthread_attr_getschedpolicy): Likewise.
* nptl/pthread_attr_getscope.c (__pthread_attr_getscope):
Likewise.
* nptl/pthread_attr_getstack.c (__pthread_attr_getstack):
Likewise.
* nptl/pthread_attr_getstackaddr.c (__pthread_attr_getstackaddr):
Likewise.
* nptl/pthread_attr_getstacksize.c (__pthread_attr_getstacksize):
Likewise.
* nptl/pthread_attr_init.c (__pthread_attr_init_2_1): Likewise.
(__pthread_attr_init_2_0): Likewise.
* nptl/pthread_attr_setdetachstate.c
(__pthread_attr_setdetachstate): Likewise.
* nptl/pthread_attr_setguardsize.c (pthread_attr_setguardsize):
Likewise.
* nptl/pthread_attr_setinheritsched.c
(__pthread_attr_setinheritsched): Likewise.
* nptl/pthread_attr_setschedparam.c
(__pthread_attr_setschedparam): Likewise.
* nptl/pthread_attr_setschedpolicy.c
(__pthread_attr_setschedpolicy): Likewise.
* nptl/pthread_attr_setscope.c (__pthread_attr_setscope):
Likewise.
* nptl/pthread_attr_setstack.c (__pthread_attr_setstack):
Likewise.
* nptl/pthread_attr_setstackaddr.c (__pthread_attr_setstackaddr):
Likewise.
* nptl/pthread_attr_setstacksize.c (__pthread_attr_setstacksize):
Likewise.
* nptl/pthread_condattr_setclock.c (pthread_condattr_setclock):
Likewise.
* nptl/pthread_create.c (__find_in_stack_list): Likewise.
* nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise.
* nptl/pthread_mutex_cond_lock.c (__pthread_mutex_lock): Define to
use internal_function.
* nptl/pthread_mutex_init.c (__pthread_mutex_init): Convert to
prototype-style function definition.
* nptl/pthread_mutex_lock.c (__pthread_mutex_lock): Likewise.
(__pthread_mutex_cond_lock_adjust): Likewise. Use
internal_function.
* nptl/pthread_mutex_timedlock.c (pthread_mutex_timedlock):
Convert to prototype-style function definition.
* nptl/pthread_mutex_trylock.c (__pthread_mutex_trylock):
Likewise.
* nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock_usercnt):
Likewise.
(__pthread_mutex_unlock): Likewise.
* nptl_db/td_ta_clear_event.c (td_ta_clear_event): Likewise.
* nptl_db/td_ta_set_event.c (td_ta_set_event): Likewise.
* nptl_db/td_thr_clear_event.c (td_thr_clear_event): Likewise.
* nptl_db/td_thr_event_enable.c (td_thr_event_enable): Likewise.
* nptl_db/td_thr_set_event.c (td_thr_set_event): Likewise.
* nss/makedb.c (process_input): Likewise.
* posix/fnmatch.c (__strchrnul): Likewise.
(__wcschrnul): Likewise.
(fnmatch): Likewise.
* posix/fnmatch_loop.c (FCT): Likewise.
* posix/glob.c (globfree): Likewise.
(__glob_pattern_type): Likewise.
(__glob_pattern_p): Likewise.
* posix/regcomp.c (re_compile_pattern): Likewise.
(re_set_syntax): Likewise.
(re_compile_fastmap): Likewise.
(regcomp): Likewise.
(regerror): Likewise.
(regfree): Likewise.
* posix/regexec.c (regexec): Likewise.
(re_match): Likewise.
(re_search): Likewise.
(re_match_2): Likewise.
(re_search_2): Likewise.
(re_search_stub): Likewise. Use internal_function
(re_copy_regs): Likewise.
(re_set_registers): Convert to prototype-style function
definition.
(prune_impossible_nodes): Likewise. Use internal_function.
* resolv/inet_net_pton.c (inet_net_pton): Convert to
prototype-style function definition.
(inet_net_pton_ipv4): Likewise.
* stdlib/strtod_l.c (____STRTOF_INTERNAL): Likewise.
* sysdeps/pthread/aio_cancel.c (aio_cancel): Likewise.
* sysdeps/pthread/aio_suspend.c (aio_suspend): Likewise.
* sysdeps/pthread/timer_delete.c (timer_delete): Likewise.
* sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise.
Make variadic.
* time/strptime_l.c (localtime_r): Convert to prototype-style
function definition.
* wcsmbs/mbsnrtowcs.c (__mbsnrtowcs): Likewise.
* wcsmbs/mbsrtowcs_l.c (__mbsrtowcs_l): Likewise.
* wcsmbs/wcsnrtombs.c (__wcsnrtombs): Likewise.
* wcsmbs/wcsrtombs.c (__wcsrtombs): Likewise.
Two glibc makefiles use -Wno-strict-prototypes. I don't know if this
was needed before my recent conversion of many function definitions to
prototype style, but it's not needed now; this patch removes it.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* posix/Makefile (CFLAGS-regex.c): Remove variable.
* resolv/Makefile (+cflags): Do not use -Wno-strict-prototypes.
This patch fixes the default wordsize-32 mmap implementation offset
calculation for negative values. Current code uses signed shift
operation to calculate the multiple size to use with syscall and
it is implementation defined. Change it to use a division base
on mmap page size (default being as before, 4096).
Tested on armv7hf.
[BZ #18877]
* posix/Makefile (tests): Add tst-mmap-offset.
* posix/tst-mmap.c: New file.
* sysdeps/unix/sysv/linux/generic/wordsize-32/mmap.c (__mmap): Fix
offset calculation for negative values.
These scripts use #!/bin/sh explicitly, so make sure they avoid echo -n
as different shells treat it differently. Use the portable printf func
instead.
These tests were skipped by the use-test-skeleton conversion done in
commit 29955b5d because they did not have an `int main (void)'
declaration. Instead their `main' functions were declared with arguments
(i.e. argc, argv) even though they didn't use them.
Remove these arguments and include the test skeleton in these tests.
Various functions in XPG4 bring in references to getlogin_r, which is
not in XPG4; this is also a bug for some older POSIX versions which
aren't yet covered by the linknamespace tests. This patch fixes this
by making getlogin_r into a weak alias for __getlogin_r and using
__getlogin_r as needed.
Tested for x86_64 and x86 (testsuite, and that disassembly of
installed stripped shared libraries is unchanged by the patch).
[BZ #18527]
* login/getlogin_r.c (getlogin_r): Rename to __getlogin_r and
define as weak alias of __getlogin_r. Use libc_hidden_weak.
* sysdeps/mach/hurd/getlogin_r.c (getlogin_r): Likewise.
* sysdeps/unix/getlogin_r.c (getlogin_r): Likewise.
* sysdeps/unix/sysv/linux/getlogin_r.c (getlogin_r): Likewise.
* include/unistd.h (__getlogin_r): Declare. Use
libc_hidden_proto.
* posix/glob.c (glob): Call __getlogin_r instead of getlogin_r.
* conform/Makefile (test-xfail-XPG3/glob.h/linknamespace): Remove
variable.
(test-xfail-XPG3/wordexp.h/linknamespace): Likewise.
(test-xfail-XPG4/glob.h/linknamespace): Likewise.
(test-xfail-XPG4/wordexp.h/linknamespace): Likewise.
aio_* bring in references to pread, which isn't in all the standards
containing aio_* (as a reference from one library to another, this is
a bug for dynamic as well as static linking). This patch fixes this
by using __libc_pread instead, exporting that function from libc at
symbol version GLIBC_PRIVATE; the code, with conditionals that may
call either __pread64 or __libc_pread, becomes exactly analogous to
that elsewhere in the same file that may call either __pwrite64 or
__libc_pwrite.
Tested for x86_64 and x86 (testsuite, and comparison of disassembly of
installed shared libraries). libc changes because of the PLT entry
for the newly exported __libc_pread; librt changes because of
assertion line numbers and PLT rearrangement; other stripped installed
shared libraries do not change.
[BZ #18519]
* posix/Versions (libc): Export __libc_pread at version
GLIBC_PRIVATE.
* sysdeps/pthread/aio_misc.c (handle_fildes_io): Call __libc_pread
instead of pread.
* conform/Makefile (test-xfail-POSIX/aio.h/linknamespace): Remove
variable.
regcomp brings in references to wcscoll, which isn't in all the
standards that contain regcomp. In turn, wcscoll brings in references
to wcscmp, also not in all those standards. This patch fixes this by
making those functions into weak aliases of __wcscoll and __wcscmp and
calling those names instead as needed.
Tested for x86_64 and x86 (testsuite, and that disassembly of
installed shared libraries is unchanged by the patch).
[BZ #18497]
* wcsmbs/wcscmp.c [!WCSCMP] (WCSCMP): Define as __wcscmp instead
of wcscmp.
(wcscmp): Define as weak alias of WCSCMP.
* wcsmbs/wcscoll.c (STRCOLL): Define as __wcscoll instead of
wcscoll.
(USE_HIDDEN_DEF): Define.
[!USE_IN_EXTENDED_LOCALE_MODEL] (wcscoll): Define as weak alias of
__wcscoll. Don't use libc_hidden_weak.
* wcsmbs/wcscoll_l.c (STRCMP): Define as __wcscmp instead of
wcscmp.
* sysdeps/i386/i686/multiarch/wcscmp-c.c
[SHARED] (libc_hidden_def): Define __GI___wcscmp instead of
__GI_wcscmp.
(weak_alias): Undefine and redefine.
* sysdeps/i386/i686/multiarch/wcscmp.S (wcscmp): Rename to
__wcscmp and define as weak alias of __wcscmp.
* sysdeps/x86_64/wcscmp.S (wcscmp): Likewise.
* include/wchar.h (__wcscmp): Declare. Use libc_hidden_proto.
(__wcscoll): Likewise.
(wcscmp): Don't use libc_hidden_proto.
(wcscoll): Likewise.
* posix/regcomp.c (build_range_exp): Call __wcscoll instead of
wcscoll.
* posix/regexec.c (check_node_accept_bytes): Likewise.
* conform/Makefile (test-xfail-XPG3/regex.h/linknamespace): Remove
variable.
(test-xfail-XPG4/regex.h/linknamespace): Likewise.
(test-xfail-POSIX/regex.h/linknamespace): Likewise.
open_memstream is new in the 2008 edition of POSIX. However, the
older functions getopt, closelog and fmtmsg all bring in references to
it. This patch fixes this in the usual way, making open_memstream
into a weak alias of __open_memstream and calling __open_memstream
from the relevant places.
Tested for x86_64 and x86 (testsuite, and that disassembly of
installed shared libraries is unchanged by the patch). 32-bit builds
produce an XPASS for conform/POSIX/unistd.h/linknamespace after this
patch (because the only cause of failure left there now is 64-bit
specific); that will disappear once the 64-bit failure is resolved and
the XFAIL removed at that time.
[BZ #18498]
* libio/memstream.c (open_memstream): Rename to __open_memstream
and define as weak alias of __open_memstream.
* include/stdio.h (__open_memstream): Declare. Use
libc_hidden_proto.
(open_memstream): Don't use libc_hidden_proto.
* misc/syslog.c (__vsyslog_chk): Call __open_memstream instead of
open_memstream.
* posix/getopt.c (_getopt_internal_r): Likewise.
* conform/Makefile (test-xfail-XPG3/stdio.h/linknamespace): Remove
variable.
(test-xfail-XPG4/stdio.h/linknamespace): Likewise.
(test-xfail-UNIX98/stdio.h/linknamespace): Likewise.
(test-xfail-XOPEN2K/unistd.h/linknamespace): Likewise.
The regex code brings in references to wcrtomb, which isn't in all the
standards that contain regex. This patch makes it call __wcrtomb
instead (in fact some places already called __wcrtomb, so this patch
makes it internally consistent about which name is used).
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
[BZ #18496]
* posix/regex_internal.c (build_wcs_upper_buffer): Call __wcrtomb
instead of wcrtomb.
regcomp brings in references to various wctype functions that aren't
in all the standards including regcomp. This patch fixes this in the
usual way by using the __* versions of these functions (which already
exist, but some didn't have libc_hidden_proto / libc_hidden_def
before).
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch). (Other wide character
function references from the regex code mean that this patch by itself
doesn't fix any XFAILed linknamespace test failures; further patches
will be needed for that.)
[BZ #18495]
* wctype/wcfuncs.c (__iswalnum): Use libc_hidden_def.
(__iswlower): Likewise.
* include/wctype.h (__iswalnum): Declare. Use libc_hidden_proto.
(__iswlower): Likewise.
* posix/regcomp.c (re_compile_fastmap_iter): Call __towlower
instead of towlower.
* posix/regex_internal.c (build_wcs_upper_buffer): Call __iswlower
instead of iswlower. Call __towupper instead of towupper.
* posix/regex_internal.h (IS_WIDE_WORD_CHAR): Call __iswalnum
instead of iswalnum.
fnmatch brings in references to strnlen, which isn't in all the
standards that contain fnmatch (not added until the 2008 edition of
POSIX), resulting in linknamespace test failures. (This is contrary
to glibc conventions, rather than a standards conformance issue,
because of the str* reservation.) This patch fixes this in the usual
way, using __strnlen instead of strnlen.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #18470]
* posix/fnmatch.c (fnmatch) [_LIBC]: Call __strnlen instead of
strnlen.
* conform/Makefile (test-xfail-XPG3/fnmatch.h/linknamespace):
Remove variable.
(test-xfail-XPG4/fnmatch.h/linknamespace): Likewise.
(test-xfail-POSIX/fnmatch.h/linknamespace): Likewise.
(test-xfail-POSIX/glob.h/linknamespace): Likewise.
(test-xfail-POSIX/wordexp.h/linknamespace): Likewise.
(test-xfail-UNIX98/fnmatch.h/linknamespace): Likewise.
(test-xfail-UNIX98/glob.h/linknamespace): Likewise.
(test-xfail-UNIX98/wordexp.h/linknamespace): Likewise.
(test-xfail-XOPEN2K/fnmatch.h/linknamespace): Likewise.
(test-xfail-XOPEN2K/glob.h/linknamespace): Likewise.
(test-xfail-XOPEN2K/wordexp.h/linknamespace): Likewise.
fnmatch brings in references to wmemchr, which isn't in all the
standards that contain fnmatch, resulting in linknamespace test
failures. This patch fixes this in the usual way, making wmemchr into
a weak alias for __wmemchr.
Tested for x86_64 and x86 (testsuite, and that disassembly of
installed shared libraries is unchanged by the patch).
[BZ #18468]
* wcsmbs/wmemchr.c (wmemchr): Rename to __wmemchr and define as
weak alias of __wmemchr. Use libc_hidden_weak.
* include/wchar.h (__wmemchr): Declare. Use libc_hidden_proto.
* posix/fnmatch.c [HANDLE_MULTIBYTE] (MEMCHR): Use __wmemchr
instead of wmemchr.
fnmatch brings in references to towlower (and thereby towupper), which
isn't in all the standards that contain fnmatch, resulting in
linknamespace test failures. (This is contrary to glibc conventions,
rather than a standards conformance issue, because of the to*
reservation.) This patch fixes this in the usual way, making those
functions into weak aliases.
Tested for x86_64 and x86 (testsuite, and that disassembly of
installed shared libraries is unchanged by the patch). This is on top
of <https://sourceware.org/ml/libc-alpha/2015-06/msg00019.html>, but
the two patches should be independent.
(The __attribute_pure__ on the declarations in include/wctype.h comes
from GCC's built-in attributes for towlower and towupper, and is
needed to get the same code generation for fnmatch before and after
the patch. It seems likely there are cases where the declaration of
__foo in the internal headers is missing attributes from foo in the
public headers, built-in to GCC or both, but I don't know a good way
to detect such missing attributes.)
[BZ #18469]
* wctype/wcfuncs.c (towlower): Rename to __towlower and define as
weak alias of __towlower. Use libc_hidden_weak.
(towupper): Rename to __towupper and define as weak alias of
__towupper. Use libc_hidden_weak.
* include/wctype.h (__towlower): Declare. Use libc_hidden_proto.
(__towupper): Likewise.
* posix/fnmatch.c [HANDLE_MULTIBYTE && _LIBC] (FOLD): Use
__towlower instead of towlower.
My review of conformtest expectations for POSIX showed up that the
_POSIX2_C_VERSION macro, required by POSIX and XPG standards before
2001, was missing in unistd.h, having been removed on 2003-04-03
despite those standards still being supported. This patch adds it
back. As it's in the implementation namespace, there's no need for it
to be conditional, and other such macros aren't conditional in this
header either.
Tested for x86_64 and x86 (testsuite). Note that this *does* change
the installed libraries, because it affects the sysconf support
(present all along) for _SC_2_C_VERSION.
[BZ #438]
* posix/unistd.h (_POSIX2_C_VERSION): New macro.
* conform/Makefile (test-xfail-POSIX/unistd.h/conform): Remove
variable.
We see some surprising warnings on tilegx with gcc 4.8.2:
In file included from regex.c:66:0:
regcomp.c: In function ‘parse_expression’:
regcomp.c:2849:15: error: ‘end_elem’ may be used uninitialized in this
function [-Werror=maybe-uninitialized]
else if (br_elem->type == COLL_SYM)
^
regcomp.c:3109:34: note: ‘end_elem’ was declared here
bracket_elem_t start_elem, end_elem;
^
regcomp.c:3109:22: error: ‘start_elem’ may be used uninitialized in
this function [-Werror=maybe-uninitialized]
bracket_elem_t start_elem, end_elem;
^
These warnings are not seen on x86, and in fact if I compile the
preprocessed tile sources with the x86 gcc 4.8.2, I don't see the
warnings. I do see eqiuvalent warnings if I compile the
x86-preprocessed source code with tilegx gcc 4.8.2.
The fix here is to initialize the union type field appropriately in
a couple of places where we pass a union pointer to a subroutine that
"knows" what type the union is. Setting the type explicitly seems like
a more robust way to manage such a data structure in any case.
This patch adds support to generate the spec array in getconf from the
conf.list. The generated code is mostly unchanged. the only changes
are due to the change in layout of the spec and val arrays in the ELF.
The val array can also be auto-generated from posix-conf-vars.list
once the remaining macros are added to it.
* posix/posix-conf-vars.list (SPEC:XBS5): Add sysconf prefix.
* posix/confstr.c: Define NEED_SPEC_ARRAY to 0.
* posix/posix-envs.def: Likewise.
* sysdeps/posix/sysconf.c: Likewise.
* posix/getconf.c: Define NEED_SPEC_ARRAY to 1.
(specs): Remove array.
* scripts/gen-posix-conf-vars.awk: Support generation of specs
array.
This fixes the remaining -Wundef warnings. Tested on x86_64.
* posix/posix-conf-vars.list: Add _POSIX sysconf namespace.
* sysdeps/posix/sysconf.c: Include posix-conf-vars.h.
(__sysconf): Use CONF_IS_* macros.
This patch adds a file posix-conf-vars.list that is used to generate
macros to determine if a macro is defined as set, unset or not
defined. gen-posix-conf-vars.awk processes this file and generates a
header (posix-conf-vars-def.h) with these macros. A new header
posix-conf-vars.h includes this generated header and defines accessor
macros for the generated macros.
Tested on x86_64.
* posix/Makefile (before-compile): Add posix-conf-vars-def.h.
($(objpfx)posix-conf-vars-def.h): New target.
* posix/posix-conf-vars.list: New file.
* posix/posix-conf-vars.h: New file.
* posix/confstr.c: Include posix-conf-vars.h.
(confstr): Use CONF_IS_* macros.
* posix/posix-envs.def: Include posix-conf-vars.h. Use
CONF_IS_* macros.
* scripts/gen-posix-conf-vars.awk: New file.
