https://sourceforge.net/p/sdcc/code/15567/
https://sourceforge.net/p/sdcc/bugs/3823/

--- sdcc/debugger/mcs51/sdcdb.c
+++ sdcc/debugger/mcs51/sdcdb.c
@@ -62,7 +62,7 @@
 int nLinkrecs = 0;
 linkrec **linkrecs = NULL; /* all linkage editor records */
 context *currCtxt = NULL;
-short fullname = 0;
+bool fullname = 0;
 short showfull = 0;
 char userinterrupt = 0;
 char nointerrupt = 0;
@@ -573,7 +573,7 @@
         {
           /* for module records do */
           case MOD_REC:
-            currMod = parseModule(loop->line, TRUE);
+            currMod = parseModule(loop->line, true);
             currModName = currMod->name ;
 
             /* search the c source file and load it into buffer */
@@ -1906,7 +1906,7 @@
 
           if (strcmp(argv[i], "-fullname") == 0)
             {
-              fullname = TRUE;
+              fullname = true;
               continue;
             }
 
--- sdcc/debugger/mcs51/sdcdb.h
+++ sdcc/debugger/mcs51/sdcdb.h
@@ -42,6 +42,7 @@
 #define Dprintf(f, fs) { }
 #endif
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -57,11 +58,6 @@
 #include "src/SDCCset.h"
 #include "src/SDCChasht.h"
 
-#define TRUE 1
-#define FALSE !TRUE
-
-typedef short bool;
-
 #ifndef max
 #define max(a,b) (a > b ? a : b)
 #endif
@@ -279,7 +275,7 @@
 char *gc_strdup(const char *s);
 srcLine **loadFile (char *name, int *nlines);
 
-extern short fullname;
+extern bool fullname;
 extern int srcMode;
 extern char contsim;
 char *searchDirsFname (char *);
--- sdcc/debugger/mcs51/symtab.c
+++ sdcc/debugger/mcs51/symtab.c
@@ -836,7 +836,7 @@
   mod = NULL;
   if (!applyToSet(modules,moduleWithCName,mname,&mod))
     {
-      mod = parseModule(mname, FALSE);
+      mod = parseModule(mname, false);
       mod->c_name = alloccpy(mname,strlen(mname));
       mod->cfullname=searchDirsFname(mod->c_name);
       mod->cLines = loadFile(mod->c_name,&mod->ncLines);