mimalloc: adjust for building inside Git

We want to compile mimalloc's source code as part of Git, rather than
requiring the code to be built as an external library: mimalloc uses a
CMake-based build, which is not necessarily easy to integrate into the
flavors of Git for Windows (which will be the main benefitting port).

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

Author: dscho

compat/mimalloc/alloc.c

@@ -15,10 +15,6 @@ terms of the MIT license. A copy of the license can be found in the file
 #include <string.h>  // memset, strlen
 #include <stdlib.h>  // malloc, exit
 
-#define MI_IN_ALLOC_C
-#include "alloc-override.c"
-#undef MI_IN_ALLOC_C
-
 // ------------------------------------------------------
 // Allocation
 // ------------------------------------------------------

compat/mimalloc/mimalloc.h

@@ -93,7 +93,8 @@ terms of the MIT license. A copy of the license can be found in the file
 // Includes
 // ------------------------------------------------------
 
-#include <stddef.h>     // size_t
+#include "git-compat-util.h"
+
 #include <stdbool.h>    // bool
 
 #ifdef __cplusplus