a make context fix

Original commit message from CVS:
a make context fix

configure.ac

@@ -3,7 +3,7 @@ AC_CANONICAL_TARGET([])
 
 dnl when going to/from release please set the nano (fourth number) right !
 dnl releases only do Wall, cvs and prerelease does Werror too
-AS_VERSION(gstreamer, GST_VERSION, 0, 4, 2, 2, GST_ERROR="-Wall", GST_ERROR="-Wall -Werror")
+AS_VERSION(gstreamer, GST_VERSION, 0, 4, 2, 3, GST_ERROR="-Wall", GST_ERROR="-Wall -Werror")
 dnl AM_MAINTAINER_MODE only provides the option to configure to enable it
 AM_MAINTAINER_MODE
 AM_INIT_AUTOMAKE($PACKAGE,$VERSION)
@@ -105,6 +105,9 @@ AC_MSG_RESULT(no)
 AC_MSG_RESULT(no)
 ])
 
+dnl check for makecontext and define HAVE_MAKECONTEXT if we have it
+GST_CHECK_MAKECONTEXT()
+
 dnl Check for essential libraries first:
 dnl ====================================
 

gst/cothreads.c

@@ -645,7 +645,7 @@ cothread_switch (cothread_state * thread)
     longjmp (thread->jmp, 1);
   }
   else {
-#ifdef HAVE_MAKECONTEXT
+#ifdef USE_MAKECONTEXT
     ucontext_t ucp;
 
     GST_DEBUG (GST_CAT_COTHREADS, "making context");

gst/gstarch.h

@@ -183,6 +183,7 @@ struct minimal_s390_stackframe {
 #elif defined(HAVE_MAKECONTEXT)
 
 /* If we have makecontext(), we'll be using that. */
+#define USE_MAKECONTEXT 1
 
 #else
 #error Need to know about this architecture, or have a generic implementation