Emit a developer-friendly message if you forget to define the proper

MCA m4 macro in configure.params (or, more likely, you copied the
configure.params file from another component and forgot to change the
m4 macro name in the file) instead of just aborting with a cryptic
message.

This commit was SVN r20181.

config/ompi_mca.m4

@@ -550,8 +550,16 @@ AC_DEFUN([MCA_CONFIGURE_M4_CONFIG_COMPONENT],[
     # try to configure the component.  pay no attention to
     # --enable-dist, since we'll always have makefiles.
     AS_IF([test "$should_build" = "1"],
-          [MCA_$2_$3_CONFIG([should_build=1], 
-                            [should_build=0])])
+          [m4_ifdef([MCA_]$2[_]$3[_CONFIG],
+                    [MCA_$2_$3_CONFIG([should_build=1], 
+                                      [should_build=0])],
+                    # If they forgot to define an MCA_<fw>_<comp>_CONFIG 
+                    # macro, print a friendly warning and abort.
+                    [AC_MSG_WARN([*** The $2:$3 did not define an])
+                     AC_MSG_WARN([*** MCA_$2_$3_CONFIG macro in the])
+                     AC_MSG_WARN([*** $1/$2/$3/configure.m4 file])
+                     AC_MSG_ERROR([Cannot continue])])
+          ])
 
     AS_IF([test "$should_build" = "1"],
           [MCA_PROCESS_COMPONENT($1, $2, $3, $4, $5, $6, $7, $compile_mode)],