add ARENA_ALLOC() macro function for arenaAllocateBlock()

src/asset.cpp

@@ -75,8 +75,7 @@ arenaCopyCStr(memory_arena* arena, const char* input, u32 max_len)
 {
 	u32 name_len = std::strlen(input) + 1;
 	assert(name_len < max_len);
-	// TODO: make an arena alloc macro
-	char* out = (char*) arenaAllocateBlock(arena, name_len);
+	char* out = ARENA_ALLOC(arena, name_len, char);
 	std::strncpy(out, input, name_len);
 	return out;
 }

src/asset.h

@@ -33,6 +33,7 @@ void arenaFree(memory_arena*& arena);
 
 uint arenaGetFreeSize(memory_arena* arena);
 
+#define ARENA_ALLOC(arena, len, type) (type*) arenaAllocateBlock(arena, len)
 void* arenaAllocateBlock(memory_arena* arena, size_t block_size);
 
 #define MAX_NAME_LENGTH 256