Check some known PATHs for mpicc in configure.

On some distributions (fedora) mpicc not installed on the default PATH.
Add a search path for finding mpicc by default if it is installed.
The user can still override the used mpicc compiler using --with-mpicc=.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14325 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.ac b/configure.ac
index 1c56455..8edc593 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2541,7 +2541,8 @@
 # Note: this is a kludge in that it assumes the specified mpicc 
 # understands -m32/-m64 regardless of what is specified using
 # --with-mpicc=.
-MPI_CC="mpicc"
+AC_PATH_PROG([MPI_CC], [mpicc], [mpicc],
+             [$PATH:/usr/lib/openmpi/bin:/usr/lib64/openmpi/bin])
 
 mflag_primary=
 if test x$VGCONF_PLATFORM_PRI_CAPS = xX86_LINUX \