[PATCH,FORTRAN] Add libcaf prototype

[David Edelsohn]

libcaf produces warnings because it defines functions without
prototypes.  This patch adds prototypes.

Bootstrapped on powerpc-ibm-aix7.1.0.0.

Thanks, David


       * libcaf.h (_gfortran_caf_critical): Add a prototype.
       (_gfortran_caf_end_critical): Same.

Index: libcaf.h
===================================================================
--- libcaf.h    (revision 198603)
+++ libcaf.h    (working copy)
@@ -76,7 +76,10 @@

 /* FIXME: The CRITICAL functions should be removed;
    the functionality is better represented using Coarray's lock feature.  */
+void _gfortran_caf_critical (void);
 void _gfortran_caf_critical (void)  { }
+
+void _gfortran_caf_end_critical (void);
 void _gfortran_caf_end_critical (void)  { }