Need to include strings.h because that is where the rindex()

function prototype lives.  Without this, we get compile 
warnings.  In addition, for 64-bit Solaris, we get a 
segmentation fault from orterun without this include.

This commit was SVN r13065.

orte/mca/pls/rsh/pls_rsh_module.c

@@ -32,6 +32,9 @@
 #endif
 #include <errno.h>
 #include <string.h>
+#ifdef HAVE_STRINGS_H
+#include <strings.h>
+#endif
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
 #endif