fixup! Import the source code of mimalloc v2.2.3

Let's ignore the `static void mi_stat_total_print()` function that is
not actually used. This is code vendored into Git, and we want to
deviate as minimally from upstream mimalloc as possible to make it cheap
to stay up to date.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

Makefile

@@ -2194,6 +2194,7 @@ $(MIMALLOC_OBJS): COMPAT_CFLAGS += -DBANNED_H
 $(MIMALLOC_OBJS): COMPAT_CFLAGS += \
 	-Wno-attributes \
 	-Wno-unknown-pragmas \
+	-Wno-unused-function \
 	-Wno-array-bounds
 
 ifdef DEVELOPER