Detect undefined PATH_MAX

POSIX does not require PATH_MAX be defined when there is not actual
limit to its value.  This affects HURD based systems.  Work around
this by defining PATH_MAX to 4096 (as on Linux) when this is not
defined.

Also, clean up inclusions of limits.h and remove autoconf check for
this header as we do not use macro shields for its inclusion anyway.

Signed-off-by: Allan McRae <allan@archlinux.org>
Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/acinclude.m4 b/acinclude.m4
index 6693da44..7309d731 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -125,3 +125,19 @@ extern int getmntinfo (struct statfs **, int);
     [Defined as the filesystem stats type ('statvfs' or 'statfs')])
 ])
 
+dnl Checks for PATH_MAX and defines it if not present
+AC_DEFUN([PATH_MAX_DEFINED],
+  [AC_CACHE_CHECK([PATH_MAX defined], path_max_cv_defined,
+    [AC_EGREP_CPP(yes, [[
+#include <limits.h>
+#if defined(PATH_MAX)
+yes
+#endif
+]],
+      [path_max_cv_defined=yes],
+      [path_max_cv_defined=no])]
+  )
+  if test $path_max_cv_defined = no; then
+    AC_DEFINE([PATH_MAX], 4096, [Define if PATH_MAX is undefined by limits.h.])
+  fi
+])