Rewrite and redesign codegen and feature system

Also switch to somewhat proper C23 flags while we're at it.

This is a huge change. It took me forever, in between being really busy.
Sorry about that. But the good news is I'm now free to start integrating
the various patches that have accumulated since last release. Well, at
least in between still being really busy. Gotta manage expectations.

The main benefit of introducing GAMESPECIFIC() is that features
that don't apply to a particular game no longer show up *at all*, and
less time is wasted on init. It also enables a cool optimisation wherein
unnecessary REQUIRE_GAMEDATA() checks can elided at compile time
whenever the gamedata is known up-front to always exist in supported
games.

The DEF_FEAT_CVAR macro family meanwhile makes it easier to manage the
lifecycle of cvars/ccmds, with less manual registering, unhiding and
such.

Originally I was going to try and just hack these features into the
existing codegen abomination, but it just got too terrible. This rewrite
should make it easier to continue tweaking codegen behaviour in future.
It also has slightly better error messages.

1 files changed, 5 insertions, 2 deletions

diff --git a/src/3p/chibicc/hashmap.c b/src/3p/chibicc/hashmap.c
index 47110c6..2090274 100644
--- a/src/3p/chibicc/hashmap.c
+++ b/src/3p/chibicc/hashmap.c
@@ -2,6 +2,9 @@
 
 #include "chibicc.h"
 
+// mike: moved from chibicc.h and also renamed, to avoid conflicts with langext.h
+#define chibi_unreachable() error("internal error at %s:%d", __FILE__, __LINE__)
+
 // Initial hash bucket size
 #define INIT_SIZE 16
 
@@ -70,7 +73,7 @@ static HashEntry *get_entry(HashMap *map, char *key, int keylen) {
     if (ent->key == NULL)
       return NULL;
   }
-  unreachable();
+  chibi_unreachable();
 }
 
 static HashEntry *get_or_insert_entry(HashMap *map, char *key, int keylen) {
@@ -102,7 +105,7 @@ static HashEntry *get_or_insert_entry(HashMap *map, char *key, int keylen) {
       return ent;
     }
   }
-  unreachable();
+  chibi_unreachable();
 }
 
 void *hashmap_get(HashMap *map, char *key) {