[PATCH 2/9] utils.c: pathconf call, check for _PC_PATH_MAX instead of HAVE_UNISTD_H.

[Pedro Alves <palves@redhat.com>]

This check in utils.c for HAVE_UNISTD_H is being used as proxy for
"HAVE_PATHCONF", as pathconf is supposed to be declared in unistd.h.

It's possible that there are systems out there that have realpath,
unistd.h and alloca, but not pathconf+_PC_PATH_MAX.  I don't know of
any by heart, but if we import gnulib's unistd module (which a
following patch will do), then unistd.h ends up always available, so
the check ends up incorrect.  As pathconf is being called with
_PC_PATH_MAX, check for that instead.

gdb/
2013-06-27  Pedro Alves  <palves@redhat.com>

	* utils.c <pathconf/_PC_PATH_MAX use>: Check if _PC_PATH_MAX is
	defined instead of checking HAVE_UNISTD_H.
---
 gdb/utils.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/utils.c b/gdb/utils.c
index f5c1339..a2015a8 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -3179,7 +3179,7 @@ gdb_realpath (const char *filename)
      pathconf()) making it impossible to pass a correctly sized buffer
      to realpath() (it could always overflow).  On those systems, we
      skip this.  */
-#if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H) && defined(HAVE_ALLOCA)
+#if defined (HAVE_REALPATH) && defined (_PC_PATH_MAX) && defined(HAVE_ALLOCA)
   {
     /* Find out the max path size.  */
     long path_max = pathconf ("/", _PC_PATH_MAX);