Check for argp_parse in libargp and then in libc before using internal version

Index: wvstreams-4.6.1/configure.ac
===================================================================
--- wvstreams-4.6.1.orig/configure.ac
+++ wvstreams-4.6.1/configure.ac
@@ -142,20 +142,21 @@ CPPFLAGS="$CPPFLAGS_save"
 # argp
 USE_WVSTREAMS_ARGP=0
 AC_CHECK_HEADERS(argp.h)
-AC_CHECK_FUNC(argp_parse)
-if test "$ac_cv_func_argp_parse" != yes \
-    -o "$ac_cv_header_argp_h" != yes ; then
-    (
-    	echo
+AC_SEARCH_LIBS([argp_parse], [argp c], [], [
+
+  if test "$ac_cv_func_argp_parse" != yes \
+      -o "$ac_cv_header_argp_h" != yes ; then
+      (
+       	echo
     	echo 'configuring argp...'
     	cd argp
     	./configure --host=$host_cpu-$host_os || exit $?
     	echo 'argp configured.'
     	echo
-    ) || exit $?
-    USE_WVSTREAMS_ARGP=1
-fi
-
+      ) || exit $?
+      USE_WVSTREAMS_ARGP=1
+  fi
+])
 # Function checks
 AC_HEADER_DIRENT
 
