Pick up ${NM} from the environment.

Upstream-Status: Pending
https://bugzilla.gnome.org/show_bug.cgi?id=671516

Signed-off-by: James Limbouris <james@digitalmatter.com.au>

Index: gdk-pixbuf-2.24.0/configure.ac
===================================================================
diff -uNr gdk-pixbuf-2.24.0/configure.ac gdk-pixbuf-2.24.0.mod/configure.ac
--- gdk-pixbuf-2.24.0/configure.ac	2011-08-27 11:27:52.000000000 +0800
+++ gdk-pixbuf-2.24.0.mod/configure.ac	2012-02-28 14:48:36.481126410 +0800
@@ -147,7 +147,7 @@
 AC_SYS_LARGEFILE
 
 AM_PROG_AS
-AC_PATH_PROG(NM, nm, nm)
+AC_CHECK_TOOLS(NM, [$NM nm], nm)
 
 AC_MSG_CHECKING([for some Win32 platform])
 AS_CASE(["$host"],