[qfcc] Implement auto as per c23

That was surprisingly easy, which makes me worried I missed something.

tools/qfcc/include/type.h

@@ -120,6 +120,7 @@ typedef struct specifier_s {
 #define VEC_TYPE(type_name, base_type) extern type_t type_##type_name;
 #include "tools/qfcc/include/vec_types.h"
 
+extern	type_t	type_auto;
 extern	type_t	type_invalid;
 extern	type_t	type_floatfield;
 

tools/qfcc/source/def.c

@@ -587,6 +587,16 @@ initialize_def (symbol_t *sym, expr_t *init, defspace_t *space,
 			sym->type = array_type (sym->type->t.array.type,
 									num_elements (init));
 		}
+		if (sym->type == &type_auto) {
+			if (init) {
+				if (!(sym->type = get_type (init))) {
+					sym->type = type_default;
+				}
+			} else {
+				error (0, "'auto' requires an initialized data declaration");
+				sym->type = type_default;
+			}
+		}
 		sym->s.def = new_def (sym->name, sym->type, space, storage);
 		reloc_attach_relocs (relocs, &sym->s.def->relocs);
 	}

tools/qfcc/source/qc-lex.l

@@ -415,6 +415,7 @@ static keyword_t at_keywords[] = {
 	{"static",		STATIC	},
 	{"sizeof",		SIZEOF	},
 	{"not",			NOT		},
+	{"auto",		TYPE_SPEC, .spec = { .type = &type_auto } },
 };
 
 // These keywords require the QuakeForge VM to be of any use. ie, they cannot

tools/qfcc/source/type.c

@@ -79,6 +79,11 @@ type_t      type_invalid = {
 	.name = "invalid",
 };
 
+type_t      type_auto = {
+	.type = ev_invalid,
+	.name = "auto",
+};
+
 #define VEC_TYPE(type_name, base_type) \
 	type_t type_##type_name = { \
 		.type = ev_##base_type, \
@@ -527,8 +532,8 @@ find_type (type_t *type)
 	type_t     *check;
 	int         i, count;
 
-	if (!type)
-		return 0;
+	if (!type || type == &type_auto)
+		return type;
 
 	if (type->freeable) {
 		switch (type->meta) {