Removed unused typedef. added some clarifications.

Copied from Perforce
 Change: 178815
 ServerID: perforce.ravenbrook.com

mps/code/prmci3li.c

@@ -40,6 +40,8 @@ MRef Prmci3AddressHoldingReg(MutatorFaultContext mfc, unsigned int regnum)
 
   /* .source.i486 */
   /* .assume.regref */
+  /* The REG_EAX etc. symbols are only present if _GNU_SOURCE is defined.
+     Currently this is in lii4gc.gmk in PFMDEFS. */
   switch (regnum) {
     case 0: return (MRef)&gregs[REG_EAX];
     case 1: return (MRef)&gregs[REG_ECX];

mps/code/protlii3.c

@@ -39,9 +39,6 @@ SRCID(protlii3, "$Id$");
 static struct sigaction sigNext;
 
 
-typedef void (*__real_lii3_sighandler_t)(int, struct sigcontext);
-
-
 /* sigHandle -- protection signal handler
  *
  *  This is the signal handler installed by ProtSetup to deal with
@@ -100,7 +97,9 @@ static void sigHandle(int sig, siginfo_t *info, void *context)  /* .sigh.args */
   }
 
   /* The exception was not handled by any known protection structure, */
-  /* so throw it to the previously installed handler. */
+  /* so throw it to the previously installed handler.  That handler won't */
+  /* get an accurate context (the MPS would fail if it were the second in */
+  /* line) but it's the best we can do. */
 
   e = sigaction(PROT_SIGNAL, &sigNext, &sa);
   AVER(e == 0);