a couple of inconsistencies

make pmatchregex regex_error_desc return type match cppregex.cpp and
posixregex.c

make the extern declaration for loadsyms[] in options.c match the
one in symbols.c.

src/options.c

@@ -95,7 +95,7 @@ static struct allopt_t allopt[SIZE(allopt_init)];
 /* use rest of file */
 
 extern char configfile[]; /* for messages */
-extern struct symparse loadsyms[];
+extern const struct symparse loadsyms[];
 #if defined(TOS) && defined(TEXTCOLOR)
 extern boolean colors_changed;  /* in tos.c */
 #endif

sys/share/pmatchregex.c

@@ -41,7 +41,7 @@ regex_compile(const char *s, struct nhregex *re)
     return TRUE;
 }
 
-const char *
+char *
 regex_error_desc(struct nhregex *re UNUSED, char *errbuf)
 {
     return strcpy(errbuf, "pattern match compilation error");