Re: [PATCH] tweak lstat.c to avoid mingw link failure

[Bruno Haible]

Jim Meyering wrote:
> I needed this patch in libvirt to avoid a link error.
> * lib/lstat.c: Include <sys/stat.h> *before* the use of stat in
> orig_stat.

This is not right: On Unix systems on which lstat is not POSIX compliant,
it will lead to an endless recursion
   rpl_lstat -> orig_lstat -> rpl_lstat -> ...

In a compilation on mingw, test-lstat.exe linked fine for me. The only
anomaly that I can see is that lstat.c is compiled, indeed with an undefined
reference to 'lstat'. It will lead to a link error when creating a shared
library. I would propose this fix instead:


2008-11-12  Bruno Haible  <address@hidden>

        * m4/lstat.m4 (gl_FUNC_LSTAT): Don't compile lstat.c on systems
        which don't have lstat; this is handled by lib/sys_stat.in.h already.
        Reported by Daniel P. Berrange via Jim Meyering.

*** m4/lstat.m4.orig    2008-11-13 03:56:56.000000000 +0100
--- m4/lstat.m4 2008-11-13 03:56:35.000000000 +0100
***************
*** 12,23 ****
  AC_DEFUN([gl_FUNC_LSTAT],
  [
    AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
!   AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
!   dnl Note: AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK does AC_LIBOBJ(lstat).
!   if test $ac_cv_func_lstat_dereferences_slashed_symlink = no; then
!     REPLACE_LSTAT=1
    fi
-   # Prerequisites of lib/lstat.c.
-   AC_REQUIRE([AC_C_INLINE])
-   :
  ])
--- 12,27 ----
  AC_DEFUN([gl_FUNC_LSTAT],
  [
    AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
!   dnl If lstat does not exist, the replacement <sys/stat.h> does
!   dnl "#define lstat stat", and lstat.c does not need to be compiled.
!   AC_CHECK_FUNCS_ONCE([lstat])
!   if test $ac_cv_func_lstat = yes; then
!     AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
!     dnl Note: AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK does AC_LIBOBJ(lstat).
!     if test $ac_cv_func_lstat_dereferences_slashed_symlink = no; then
!       REPLACE_LSTAT=1
!     fi
!     # Prerequisites of lib/lstat.c.
!     AC_REQUIRE([AC_C_INLINE])
    fi
  ])