lstat: Fix compilation error in C++ mode on mingw

[Bruno Haible]

In a testdir build on mingw, I get this compilation error:

depbase=`echo test-sys_stat-c++.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
x86_64-w64-mingw32-g++ -DHAVE_CONFIG_H -DEXEEXT=\".exe\" -I. -I../../gltests 
-I..  -DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. -I../../gltests -I.. 
-I../../gltests/.. -I../gllib -I../../gltests/../gllib 
-D_WIN32_WINNT=_WIN32_WINNT_WINXP -I/usr/local/mingw64/include -Wall  
-Wno-error -g -O2 -MT test-sys_stat-c++.o -MD -MP -MF $depbase.Tpo -c -o 
test-sys_stat-c++.o ../../gltests/test-sys_stat-c++.cc &&\
mv -f $depbase.Tpo $depbase.Po
In file included from /usr/x86_64-w64-mingw32/sys-root/mingw/include/io.h:10:0,
                 from 
/usr/x86_64-w64-mingw32/sys-root/mingw/include/unistd.h:10,
                 from ../gllib/unistd.h:40,
                 from ../gllib/time.h:44,
                 from ../gllib/sys/stat.h:44,
                 from ../../gltests/test-sys_stat-c++.cc:22:
../gllib/sys/stat.h: In member function 'gnulib::_gl_lstat_wrapper::operator 
gnulib::_gl_lstat_wrapper::type() const':
../gllib/sys/stat.h:1113:1: error: expected primary-expression before ';' token
 _GL_CXXALIAS_RPL_1 (lstat, stat, int,
 ^
make[4]: *** [Makefile:23382: test-sys_stat-c++.o] Error 1

The reason is that 'lstat' expands to 'stat', which expands to 'rpl_stat', but
the function rpl_stat() is not yet declared at this point.

This patch fixes it.


2022-09-04  Bruno Haible  <bruno@clisp.org>

        lstat: Fix compilation error in C++ mode on mingw.
        * lib/sys_stat.h (lstat): Move declaration after the declaration of
        'stat'.

diff --git a/lib/sys_stat.in.h b/lib/sys_stat.in.h
index 714c3cb189..0ec320f58c 100644
--- a/lib/sys_stat.in.h
+++ b/lib/sys_stat.in.h
@@ -596,44 +596,6 @@ _GL_WARN_ON_USE (lchmod, "lchmod is unportable - "
 #endif
 
 
-#if @GNULIB_LSTAT@
-# if ! @HAVE_LSTAT@
-/* mingw does not support symlinks, therefore it does not have lstat.  But
-   without links, stat does just fine.  */
-#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
-#   define lstat stat
-#  endif
-_GL_CXXALIAS_RPL_1 (lstat, stat, int,
-                    (const char *restrict name, struct stat *restrict buf));
-# elif @REPLACE_LSTAT@
-#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
-#   undef lstat
-#   define lstat rpl_lstat
-#  endif
-_GL_FUNCDECL_RPL (lstat, int,
-                  (const char *restrict name, struct stat *restrict buf)
-                  _GL_ARG_NONNULL ((1, 2)));
-_GL_CXXALIAS_RPL (lstat, int,
-                  (const char *restrict name, struct stat *restrict buf));
-# else
-_GL_CXXALIAS_SYS (lstat, int,
-                  (const char *restrict name, struct stat *restrict buf));
-# endif
-# if @HAVE_LSTAT@
-_GL_CXXALIASWARN (lstat);
-# endif
-#elif @GNULIB_OVERRIDES_STRUCT_STAT@
-# undef lstat
-# define lstat lstat_used_without_requesting_gnulib_module_lstat
-#elif defined GNULIB_POSIXCHECK
-# undef lstat
-# if HAVE_RAW_DECL_LSTAT
-_GL_WARN_ON_USE (lstat, "lstat is unportable - "
-                 "use gnulib module lstat for portability");
-# endif
-#endif
-
-
 #if @GNULIB_MKDIR@
 # if @REPLACE_MKDIR@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
@@ -895,6 +857,44 @@ _GL_WARN_ON_USE (stat, "stat is unportable - "
 #endif
 
 
+#if @GNULIB_LSTAT@
+# if ! @HAVE_LSTAT@
+/* mingw does not support symlinks, therefore it does not have lstat.  But
+   without links, stat does just fine.  */
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define lstat stat
+#  endif
+_GL_CXXALIAS_RPL_1 (lstat, stat, int,
+                    (const char *restrict name, struct stat *restrict buf));
+# elif @REPLACE_LSTAT@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef lstat
+#   define lstat rpl_lstat
+#  endif
+_GL_FUNCDECL_RPL (lstat, int,
+                  (const char *restrict name, struct stat *restrict buf)
+                  _GL_ARG_NONNULL ((1, 2)));
+_GL_CXXALIAS_RPL (lstat, int,
+                  (const char *restrict name, struct stat *restrict buf));
+# else
+_GL_CXXALIAS_SYS (lstat, int,
+                  (const char *restrict name, struct stat *restrict buf));
+# endif
+# if @HAVE_LSTAT@
+_GL_CXXALIASWARN (lstat);
+# endif
+#elif @GNULIB_OVERRIDES_STRUCT_STAT@
+# undef lstat
+# define lstat lstat_used_without_requesting_gnulib_module_lstat
+#elif defined GNULIB_POSIXCHECK
+# undef lstat
+# if HAVE_RAW_DECL_LSTAT
+_GL_WARN_ON_USE (lstat, "lstat is unportable - "
+                 "use gnulib module lstat for portability");
+# endif
+#endif
+
+
 #if @GNULIB_MDA_UMASK@
 /* On native Windows, map 'umask' to '_umask', so that -loldnames is not
    required.  In C++ with GNULIB_NAMESPACE, avoid differences between