bug#60971: build failure of v3.0.9rc1 on mac os 12.6

[lloda <lloda@sarc.name>]

Hello,

v3.0.9rc1 fails on mac os 12.6.2 & gcc 12.2 or clang 14, same error in either case. gcc's error is:

------------------------------------
CC       libguile_3.0_la-posix.lo
In file included from ../../../src/guile4/libguile/posix.c:82:
../../../src/guile4/libguile/posix.c:109:9: error: lvalue required as unary '&' operand
  109 | verify (WEXITSTATUS (W_EXITCODE (127, 0)) == 127);
      |         ^~~~~~~~~~~
../../../src/guile4/lib/verify.h:213:57: note: in definition of macro '_GL_VERIFY'
  213 | # define _GL_VERIFY(R, DIAGNOSTIC, ...) _Static_assert (R, DIAGNOSTIC)
      |                                                         ^
../../../src/guile4/libguile/posix.c:109:1: note: in expansion of macro 'verify'
  109 | verify (WEXITSTATUS (W_EXITCODE (127, 0)) == 127);
      | ^~~~~~
../../../src/guile4/libguile/posix.c:109:9: error: expression in static assertion is not an integer
  109 | verify (WEXITSTATUS (W_EXITCODE (127, 0)) == 127);
      |         ^~~~~~~~~~~
../../../src/guile4/lib/verify.h:213:57: note: in definition of macro '_GL_VERIFY'
  213 | # define _GL_VERIFY(R, DIAGNOSTIC, ...) _Static_assert (R, DIAGNOSTIC)
      |                                                         ^
../../../src/guile4/libguile/posix.c:109:1: note: in expansion of macro 'verify'
  109 | verify (WEXITSTATUS (W_EXITCODE (127, 0)) == 127);
      | ^~~~~~
------------------------------------

The problematic section in libguile/posix.c

...

#if HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif
#ifndef WEXITSTATUS
# define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
#endif
#ifndef WIFEXITED
# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
#endif

#ifndef W_EXITCODE
/* Macro for constructing a status value.  Found in glibc.  */
# ifdef _WIN32                            /* see Gnulib's posix-w32.h */
#  define W_EXITCODE(ret, sig)   (ret)
# else
#  define W_EXITCODE(ret, sig)   ((ret) << 8 | (sig))
# endif
#endif
verify (WEXITSTATUS (W_EXITCODE (127, 0)) == 127);
...

adding -o .libs/libguile_3.0_la-posix.i -E to the build line shows line 109 as

_Static_assert ( (((*(int *)&((( 127 ) << 8 | ( 0 )))) >> 8) & 0x000000ff) == 127, "verify (" "WEXITSTATUS (W_EXITCODE (127, 0)) == 127" ")");
                            ^

forcing redefinition of WEXITSTATUS shows the previous definition at /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/wait.h

...

#if defined(_POSIX_C_SOURCE) && !defined(_DARWIN_C_SOURCE)
#define _W_INT(i)       (i)
#else
#define _W_INT(w)       (*(int *)&(w))  /* convert union wait to int */   <------------- problem
#define WCOREFLAG       0200
#endif /* (_POSIX_C_SOURCE && !_DARWIN_C_SOURCE) */

/* These macros are permited, as they are in the implementation namespace */
#define _WSTATUS(x)     (_W_INT(x) & 0177)
#define _WSTOPPED       0177            /* _WSTATUS if process is stopped */

/*
 * [XSI] The <sys/wait.h> header shall define the following macros for
 * analysis of process status values
 */
#if __DARWIN_UNIX03
#define WEXITSTATUS(x)  ((_W_INT(x) >> 8) & 0x000000ff)
#else /* !__DARWIN_UNIX03 */
#define WEXITSTATUS(x)  (_W_INT(x) >> 8)
#endif /* !__DARWIN_UNIX03 */
/* 0x13 == SIGCONT */
#define WSTOPSIG(x)     (_W_INT(x) >> 8)
#define WIFCONTINUED(x) (_WSTATUS(x) == _WSTOPPED && WSTOPSIG(x) == 0x13)
#define WIFSTOPPED(x)   (_WSTATUS(x) == _WSTOPPED && WSTOPSIG(x) != 0x13)
#define WIFEXITED(x)    (_WSTATUS(x) == 0)
#define WIFSIGNALED(x)  (_WSTATUS(x) != _WSTOPPED && _WSTATUS(x) != 0)
#define WTERMSIG(x)     (_WSTATUS(x))
#if (!defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE))
#define WCOREDUMP(x)    (_W_INT(x) & WCOREFLAG)

#define W_EXITCODE(ret, sig)    ((ret) << 8 | (sig))
#define W_STOPCODE(sig)         ((sig) << 8 | _WSTOPPED)
#endif /* (!defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)) */

...

so that's the problem, but I'm not sure what the solution is. The way it's
written, W_EXITCODE() is always going to give up a number...

Thanks

  Daniel