Use alloca instead of a c++ vla for W_HashLumpName

src/CMakeLists.txt

@@ -534,7 +534,6 @@ target_compile_options(SRB2SDL2 PRIVATE
 		-Wno-unused-function
 		-Wno-unused-but-set-variable
 		-Wno-unused-private-field
-		-Wno-vla-extension
 	>
 
 	# GNU

src/w_wad.cpp

@@ -462,7 +462,7 @@ FUNCINLINE static ATTRINLINE void W_InvalidateLumpnumCache(void)
 
 FUNCINLINE static ATTRINLINE UINT32 W_HashLumpName(const char *name, size_t len)
 {
-	char uname[len + 1];
+	char *uname = (char *)alloca(len + 1);
 	strlcpy(uname, name, len + 1);
 	strupr(uname);
 	return HASH32(uname, len);