Inital context stuff and tests

Linking and  building is successfull and inital tests pass

tests/smoke.c

@@ -0,0 +1,70 @@
+#include "../include/regolith.h"
+#include "../include/regolith_lua.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct counter {
+  size_t live;
+  size_t peak;
+} counter;
+
+static void track(counter *c, size_t add, size_t sub) {
+  c->live = c->live + add - sub;
+  if (c->live > c->peak)
+    c->peak = c->live;
+}
+
+static void *c_alloc(size_t size, void *user) {
+  void *p = malloc(size);
+  if (p)
+    track(user, size, 0);
+  return p;
+}
+
+static void *c_realloc(void *ptr, size_t old_size, size_t new_size,
+                       void *user) {
+  void *p = realloc(ptr, new_size);
+  if (p)
+    track(user, new_size, old_size);
+  return p;
+}
+
+static void c_free(void *ptr, size_t size, void *user) {
+  track(user, 0, size);
+  free(ptr);
+}
+
+int main(void) {
+  counter c = {0, 0};
+  rg_config cfg;
+  rg_context *ctx;
+  int rc;
+
+  rg_config_init(&cfg);
+  cfg.allocator.alloc = c_alloc;
+  cfg.allocator.realloc = c_realloc;
+  cfg.allocator.free = c_free;
+  cfg.allocator.user = &c;
+
+  ctx = rg_create(&cfg);
+  if (!ctx)
+    return 1;
+
+  rc = rg_lua_open(ctx);
+  if (rc == RG_OK)
+    rc = rg_lua_dostring(ctx, "print('hello from ' .. _VERSION)", "=smoke");
+  if (rc == RG_OK)
+    rc = rg_lua_dostring(ctx, "this is not lua", "=smoke_bad") == RG_ERR_LUA
+             ? RG_OK
+             : RG_ERR_GENERIC;
+
+  printf("regolith %s, peak %zu bytes\n", rg_version(), c.peak);
+  rg_destroy(ctx);
+
+  if (c.live != 0) {
+    printf("leak: %zu bytes still live\n", c.live);
+    return 1;
+  }
+  return rc == RG_OK ? 0 : 1;
+}

tests/smoke_sdl3.c

@@ -0,0 +1,9 @@
+#include <SDL3/SDL.h>
+#include <stdio.h>
+
+int main(void)
+{
+    int v = SDL_GetVersion();
+    printf("SDL %d.%d.%d\n", SDL_VERSIONNUM_MAJOR(v), SDL_VERSIONNUM_MINOR(v), SDL_VERSIONNUM_MICRO(v));
+    return 0;
+}