check for missing statfs() prototype (happens at least under AIX 4)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@35288 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

configure.in

@@ -4135,10 +4135,10 @@ AC_CACHE_CHECK(for statfs, wx_cv_func_statfs,
     AC_TRY_COMPILE(
         [
              #if defined(__BSD__)
-               #include <sys/param.h>
-               #include <sys/mount.h>
+             #include <sys/param.h>
+             #include <sys/mount.h>
              #else
-               #include <sys/vfs.h>
+             #include <sys/vfs.h>
              #endif
         ],
         [
@@ -4149,16 +4149,37 @@ AC_CACHE_CHECK(for statfs, wx_cv_func_statfs,
              l += fs.f_blocks;
              l += fs.f_bavail;
         ],
-        [
-             wx_cv_func_statfs=yes
-        ],
-        [
-             wx_cv_func_statfs=no
-        ]
+         wx_cv_func_statfs=yes,
+         wx_cv_func_statfs=no
     )
 )
 
 if test "$wx_cv_func_statfs" = "yes"; then
+    dnl check whether we have its dcelaration too: some systems (AIX 4) lack it
+    AC_LANG_SAVE
+    AC_LANG_CPLUSPLUS
+    AC_CACHE_CHECK(for statfs declaration, wx_cv_func_statfs_decl,
+        [
+             #if defined(__BSD__)
+             #include <sys/param.h>
+             #include <sys/mount.h>
+             #else
+             #include <sys/vfs.h>
+             #endif
+        ],
+        [
+            struct statfs fs;
+            statfs("", &fs);
+        ],
+        wx_cv_func_statfs_decl=yes,
+        wx_cv_func_statfs_decl=no
+    )
+    AC_LANG_RESTORE
+
+    if test "$wx_cv_func_statfs_decl" = "yes"; then
+        AC_DEFINE(HAVE_STATFS_DECL)
+    fi
+
     wx_cv_type_statvfs_t="struct statfs"
     AC_DEFINE(HAVE_STATFS)
 else