fix: add null checks and bounds validation for memory safety

clang/parse/auto_dup.c

@@ -62,7 +62,7 @@ fn void auto_dup_go(u64 loc, u32 lvl, u32 base, u32 *use, u32 n, u32 lab, u8 tgt
   }
 
   // Shift outer refs
-  if ((tg == BJV || tg == BJ0 || tg == BJ1) && vl > base) {
+  if ((tg == BJV || tg == BJ0 || tg == BJ1 || tg == BJM) && vl > base) {
     HEAP[loc] = term_new(0, tg, term_ext(t), vl + n);
     return;
   }

clang/parse/include.c

@@ -26,7 +26,11 @@ fn void parse_include(PState *s) {
   if (PARSE_SEEN_FILES_LEN >= 1024) {
     sys_error("MAX_INCLUDES");
   }
-  PARSE_SEEN_FILES[PARSE_SEEN_FILES_LEN++] = strdup(path);
+  char *path_copy = strdup(path);
+  if (!path_copy) {
+    sys_error("out of memory in parse_include");
+  }
+  PARSE_SEEN_FILES[PARSE_SEEN_FILES_LEN++] = path_copy;
 
   // Read and parse
   char *src = sys_file_read(path);

clang/parse/term/str.c

@@ -13,6 +13,9 @@ fn Term parse_term_str(PState *s, u32 depth) {
     } else {
       c = parse_utf8(s);
     }
+    if (n >= 4096) {
+      parse_error(s, "string too long (max 4096 codepoints)", '"');
+    }
     cs[n++] = c;
   }
   parse_advance(s);

clang/table/find.c

@@ -11,6 +11,9 @@ fn u32 table_find(const char *name, u32 len) {
   // Not found - create new entry
   u32  id   = TABLE_LEN++;
   char *copy = malloc(len + 1);
+  if (!copy) {
+    sys_error("out of memory in table_find");
+  }
   memcpy(copy, name, len);
   copy[len] = '\0';
   TABLE[id] = copy;