break compilation with a more helpful error at least if MPI 1.x is detected

git-svn-id: https://svn.mcs.anl.gov/repos/darshan/trunk@382 3b7491f3-a168-0410-bf4b-c445ed680a29

lib/darshan-mpi-io.c

@@ -31,6 +31,10 @@
 #include <dlfcn.h>
 #include <stdlib.h>
 
+#if MPI_VERSION < 2
+#error Darshan does not yet support MPI 1.x
+#endif
+
 #define DARSHAN_MPI_CALL(func) __real_ ## func
 
 #define DARSHAN_FORWARD_DECL(name,ret,args) \