Fix compilation warnings in Lua and jemalloc dependencies (#7785)

- The argument `u` in for `ar` is ignored (and generates warnings since `D` became the default.
  All it does is avoid updating unchanged objects (shouldn't have any impact on our build)
- Enable `LUA_USE_MKSTEMP` to force the use of `mkstemp()` instead of `tmpname()` (which is dead
  code in redis anyway).
- Remove unused variable `c` in `f_parser()`
- Removed misleadingly indented space in `luaL_loadfile()` and ``addfield()`

Co-authored-by: Oran Agra <oran@redislabs.com>

deps/Makefile

@@ -69,13 +69,13 @@ ifeq ($(uname_S),SunOS)
 	LUA_CFLAGS= -D__C99FEATURES__=1
 endif
 
-LUA_CFLAGS+= -O2 -Wall -DLUA_ANSI -DENABLE_CJSON_GLOBAL -DREDIS_STATIC='' $(CFLAGS)
+LUA_CFLAGS+= -O2 -Wall -DLUA_ANSI -DENABLE_CJSON_GLOBAL -DREDIS_STATIC='' -DLUA_USE_MKSTEMP $(CFLAGS)
 LUA_LDFLAGS+= $(LDFLAGS)
 # lua's Makefile defines AR="ar rcu", which is unusual, and makes it more
 # challenging to cross-compile lua (and redis).  These defines make it easier
 # to fit redis into cross-compilation environments, which typically set AR.
 AR=ar
-ARFLAGS=rcu
+ARFLAGS=rc
 
 lua: .make-prerequisites
 	@printf '%b %b\n' $(MAKECOLOR)MAKE$(ENDCOLOR) $(BINCOLOR)$@$(ENDCOLOR)

deps/jemalloc/configure.ac

@@ -512,7 +512,7 @@ CTARGET='-o $@'
 LDTARGET='-o $@'
 TEST_LD_MODE=
 EXTRA_LDFLAGS=
-ARFLAGS='crus'
+ARFLAGS='crs'
 AROUT=' $@'
 CC_MM=1
 

deps/lua/src/ldo.c

@@ -493,7 +493,7 @@ static void f_parser (lua_State *L, void *ud) {
   Proto *tf;
   Closure *cl;
   struct SParser *p = cast(struct SParser *, ud);
-  int c = luaZ_lookahead(p->z);
+  luaZ_lookahead(p->z);
   luaC_checkGC(L);
   tf = (luaY_parser)(L, p->z,
                                                              &p->buff, p->name);