在使用 clang22 为 armv7 ios 构建时触发的 Wincompatible-pointer-types

When building with the combination of clang22, ios 13 sdk, and armv7 target, libgit2 fails to build due to `size_t` being declared as `unsigned long`, and thus being a mismatched type when passed to the various `GIT_XXX_SIZET_OVERFLOW`, `GIT_ERROR_CHECK_ALLOC_ADD`. This build log is for libgit 1.8.5, but the issue is present in the current master branch as well