dthelp: fix implicit-function-declaration warnings (the rest)

... at least with regard to the non-generated code.

cde/programs/dthelp/parser/canon1/helptag/help.c

@@ -32,6 +32,8 @@
 #include "LocaleXlate.h"
 #include "XlationSvc.h"
 
+void m_mberr1(char *text, const char *arg);
+
 void assert_hometopic_exists(void)
 {
 static const char hometopic[] = "-HOMETOPIC";

cde/programs/dthelp/parser/canon1/helptag/option.c

@@ -37,6 +37,8 @@
 #define TAGDOTOPT "helptag.opt"
 #define DOTOPT ".opt"
 
+void m_mberr1(char *text, const char *arg);
+
 void options(LOGICAL filelenonly)
 {
 int i;

cde/programs/dthelp/parser/canon1/helptag/special.c

@@ -121,6 +121,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <strings.h>
 
 typedef wchar_t M_WCHAR;
 
@@ -147,9 +148,9 @@ if (argc < 3)
     { /*  Either one argument or none; not more */
     if (argc == 2)
 	{
-	if (!stricmp(argv[1], "b")) both = TRUE;
-	else if (!stricmp(argv[1], "s")) spec = TRUE;
-	else if (!stricmp(argv[1], "c")) coll = TRUE;
+	if (!strcasecmp(argv[1], "b")) both = TRUE;
+	else if (!strcasecmp(argv[1], "s")) spec = TRUE;
+	else if (!strcasecmp(argv[1], "c")) coll = TRUE;
 	else error = TRUE;
 	}
     else both = TRUE;

cde/programs/dthelp/parser/canon1/parser/scan.c

@@ -47,6 +47,8 @@ This product and information is proprietary of Tandem Computers Incorporated.
 #include "entity2.h"
 #include "sref.h"
 
+void m_mberr1(char *text, const char *arg);
+
 /* Actually read a character from an input stream */
 int m_actgetc(void)
   {