mimalloc override + valgrind

Hi,

if you use valgrind for debugging (which is often very useful), this works ok with mimalloc and override beside that for the free's (if you use C++), you will get a lot of warnings about mismatching delete/delete[]/free usage.

Example:

==171393== Mismatched free() / delete / delete []
==171393== at 0x483A9AB: free (vg_replace_malloc.c:540)
==171393== by 0x317E26: Ur::MessageHandler::~MessageHandler() (in /home/cullmann/projects/build/libur.default.release/libur/test/test_gcallocator_exe)
==171393== by 0x2FF2FC: Ur::StaticInitializer::~StaticInitializer() (in /home/cullmann/projects/build/libur.default.release/libur/test/test_gcallocator_exe)
==171393== by 0x4A53536: __run_exit_handlers (in /usr/lib/libc-2.31.so)
==171393== by 0x4A536ED: exit (in /usr/lib/libc-2.31.so)
==171393== by 0x4A3C029: (below main) (in /usr/lib/libc-2.31.so)
==171393== Address 0x4be0420 is 0 bytes inside a block of size 64 alloc'd
==171393== at 0x483A50F: operator new[](unsigned long) (vg_replace_malloc.c:433)
==171393== by 0x3174D6: Ur::MessageHandler::MessageHandler() (in /home/cullmann/projects/build/libur.default.release/libur/test/test_gcallocator_exe)
==171393== by 0x2FF170: Ur::StaticInitializer::StaticInitializer() (in /home/cullmann/projects/build/libur.default.release/libur/test/test_gcallocator_exe)
==171393== by 0x2C4CFD: _GLOBAL__sub_I_test_gcallocator.cpp (in /home/cullmann/projects/build/libur.default.release/libur/test/test_gcallocator_exe)
==171393== by 0x48189C: __libc_csu_init (in /home/cullmann/projects/build/libur.default.release/libur/test/test_gcallocator_exe)
==171393== by 0x4A3BFAF: (below main) (in /usr/lib/libc-2.31.so)

This can be avoided, if one doesn't redirect directly but still do an extra call inside the overriding by enforcing to use the

#define MI_FORWARD1(fun,x) { return fun(x); }

variant of forwarding.

Would it be possible to have this as a cmake option? I can patch that file to always use this variant, but I assume other people will stumble over this sooner or later, too.

(or is there some more appropriate way to handle this?)

Start by locating the CMake options and the override-forwarding definitions that use MI_FORWARD1, then reproduce the mismatched free/delete warnings with Valgrind. Done means a CMake-selectable forwarding mode uses the extra call for overrides and the reported warnings are resolved.

Written by the indexing model from the issue text.