Fix GCC11-only errors and warnings

meson.build

@@ -175,7 +175,7 @@ if copt_msvc
 	project_c_args += args_msvc
 	project_cpp_args += args_msvc
 else
-	args_ccomp = [ '-U__STRICT_ANSI__', '-Wno-unused-result' ]
+	args_ccomp = [ '-Wno-unused-result' ]
 	if copt_platform == 'mac'
 		if uopt_x86_sse_level >= 0
 			message('SSE level explicitly configured but unavailable on macosx')

src/bzip2/bz2wrap.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstddef>
 #include <vector>
 
 enum BZ2WCompressResult

src/lua/LuaBit.cpp

@@ -99,7 +99,9 @@ static int bit_bnot(lua_State *L) { BRET(~barg(L, 1)) }
 
 #define BIT_OP(func, opr) \
   static int func(lua_State *L) { int i; UBits b = barg(L, 1); \
-    for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); BRET(b) }
+    for (i = lua_gettop(L); i > 1; i--) b opr barg(L, i); \
+    BRET(b) \
+  }
 BIT_OP(bit_band, &=)
 BIT_OP(bit_bor, |=)
 BIT_OP(bit_bxor, ^=)