Emit an error (instead of a SEGV) if the "compiler" parameter is not set

in the wrapper data file.

This commit was SVN r24190.

opal/tools/wrappers/help-opal-wrapper.txt

@@ -10,8 +10,7 @@
 #                         University of Stuttgart.  All rights reserved.
 # Copyright (c) 2004-2005 The Regents of the University of California.
 #                         All rights reserved.
-# Copyright (c) 2006      Sun Microsystems, Inc.  All rights reserved.
-#                         Use is subject to license terms.
+# Copyright (c) 2006-2010 Oracle and/or its affiliates.  All rights reserved.
 # $COPYRIGHT$
 # 
 # Additional copyrights may follow
@@ -31,6 +30,10 @@ indicating use of MPI profiling layer.  However, Open MPI was not
 compiled with support for the MPI profiling layer.  This flag has
 therefore been ignored.
 #
+[no-compiler-specified]
+No underlying compiler was specified in the wrapper compiler data file
+(e.g., mpicc-wrapper-data.txt)
+#
 [no-compiler-found]
 The Open MPI wrapper compiler was unable to find the specified compiler
 %s in your PATH.

opal/tools/wrappers/opal_wrapper.c

@@ -724,6 +724,13 @@ main(int argc, char *argv[])
         exec_argc = 0;
     }
 
+    /* This error would normally not happen unless the user edits the 
+       wrapper data files manually */
+    if (NULL == exec_argv) {
+        opal_show_help("help-opal-wrapper.txt", "no-compiler-specified", true);
+        return 1;
+    }
+
     if (flags & COMP_WANT_COMPILE) {
         opal_argv_insert(&exec_argv, exec_argc,
                          options_data[user_data_idx].comp_flags_prefix);