tt/mini_isam: add new isam_prototypes.h include file and fix up problems

There were a variety of potential 64b problems due to the complete
lack of prototype declarations.  So, we add a file, isam_prototypes.h,
generated mostly by the 'cproto' tool.

We also fixed up some errors that having proper prototypes pointed
out, mainly in passing ints where pointers were expected and vice
versa.  The iserase() function was supposed to accept a char *, but
was defined as only accepting a char.  Fun stuff like that.

cde/lib/tt/mini_isam/iserror.c

@@ -38,6 +38,7 @@
  */
 
 #include "isam_impl.h"
+#include <unistd.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <syslog.h>
@@ -81,8 +82,6 @@ _isfatal_error(char *msg)
 void 
 _isfatal_error1(char *msg)
 {
-  extern int	_is_rpcnetisamd; /* is 1 if this is rpc.netisamd */
-  extern int	_is_netisamlockd; /* is 1 if this is netisamlockd */
   int		logerr;
 
   if (fatal_error_user_handler) {
@@ -113,14 +112,17 @@ _isam_warning(char *msg)
 }
 
 /* Set user specified fatal_error handler */
-int  (*_isfatal_error_set_func(int(*func)()))()
+int  _isfatal_error_set_func(int(*func)())
 {
+#if 0
     int		(*oldfunc)();
 
     oldfunc = fatal_error_user_handler;
+#endif
+
     fatal_error_user_handler = func;
 
-    return (oldfunc);
+    return (0);
 }
 
 /*