Cleanup (#826)

* Update meson.build
- add logic to loop over more lua names (in the future more names might be discovered)
- disable warnings and errors on dependencies

* adding missing includes and checks, correct data types, pointer mess […]
- various functions from string.h were used but never defined
- logic was done across multiple different data types with different signedness, got all of them up to snuff
- give 0 sized array size of 1 (array of size 0 is illegal, but rewriting the code is out of the scope of this commit)
- add preprocessor that marks possibly unused argument as such (does not mean they will get optimized out or anything)
- correctly initialize structs with all data needed

All these were found by generating the project using `meson -Dwarning_level=3 -Dwerror=true`

* remove undefined behavior, correct data types

* Comment manual bit manipulation to be investigated

* check for more edge cases, replace multiple cleanups with goto

* remove system specific includes

src/rencache.h

@@ -8,10 +8,9 @@
 void  rencache_show_debug(bool enable);
 void  rencache_set_clip_rect(RenRect rect);
 void  rencache_draw_rect(RenRect rect, RenColor color);
-float rencache_draw_text(lua_State *L, RenFont **font, 
-  const char *text, float x, int y, RenColor color);
+float rencache_draw_text(RenFont **font, const char *text, float x, int y, RenColor color);
 void  rencache_invalidate(void);
-void  rencache_begin_frame(lua_State *L);
-void  rencache_end_frame(lua_State *L);
+void  rencache_begin_frame();
+void  rencache_end_frame();
 
 #endif