Use pkg-config first to look for external libnsl which is now
split out from glibc, if it does not exist then see if its provided
by glibc itself.

-Khem

Index: autofs-5.1.2/configure.in
===================================================================
--- autofs-5.1.2.orig/configure.in
+++ autofs-5.1.2/configure.in
@@ -186,7 +186,7 @@ fi
 #
 # glibc/libc 6 new libraries
 #
-AC_CHECK_LIB(nsl, yp_match, LIBNSL="-lnsl")
+PKG_CHECK_MODULES([NSL], [libnsl], [], [AC_CHECK_LIB([nsl],[yp_match],[LIBNSL="-lnsl"],[LIBNSL=""])])
 AC_SUBST(LIBNSL)
 
 AC_CHECK_LIB(resolv, res_query, LIBRESOLV="-lresolv")