Merge 7023c205aa into fae61ed946

I've got a failure while trying to compile with "-mmacosx-version-min=10.7" since MAC_OS_X_VERSION_MAX_ALLOWED is greater than MAC_OS_X_VERSION_10_15 but still we can't use `aligned_alloc` since of the lower bound (10.7).
I'm not sure about internal details of how `__OSX_AVAILABLE` works, but my hope is the it would only make this interpose available starting from the OS version specified.
Also, it helps me to compile mimalloc with "-mmacosx-version-min=10.7".

src/alloc-override.c

@@ -77,18 +77,12 @@ typedef void* mi_nothrow_t;
     MI_INTERPOSE_MI(calloc),
     MI_INTERPOSE_MI(realloc),
     MI_INTERPOSE_MI(strdup),
-    #if defined(MAC_OS_X_VERSION_10_7) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
-    MI_INTERPOSE_MI(strndup),
-    #endif
     MI_INTERPOSE_MI(realpath),
     MI_INTERPOSE_MI(posix_memalign),
     MI_INTERPOSE_MI(reallocf),
     MI_INTERPOSE_MI(valloc),
     MI_INTERPOSE_FUN(malloc_size,mi_malloc_size_checked),
     MI_INTERPOSE_MI(malloc_good_size),
-    #if defined(MAC_OS_X_VERSION_10_15) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_15
-    MI_INTERPOSE_MI(aligned_alloc),
-    #endif
     #ifdef MI_OSX_ZONE
     // we interpose malloc_default_zone in alloc-override-osx.c so we can use mi_free safely
     MI_INTERPOSE_MI(free),
@@ -99,6 +93,15 @@ typedef void* mi_nothrow_t;
     MI_INTERPOSE_FUN(vfree,mi_cfree),
     #endif
   };
+  __attribute__((used)) static struct mi_interpose_s _mi_interposes_10_7[]
+  __attribute__((section("__DATA, __interpose"))) __OSX_AVAILABLE(10.7) = {
+      MI_INTERPOSE_MI(strndup),
+};
+
+  __attribute__((used)) static struct mi_interpose_s _mi_interposes_10_15[]
+      __attribute__((section("__DATA, __interpose"))) __OSX_AVAILABLE(10.15) = {
+          MI_INTERPOSE_MI(aligned_alloc),
+  };
 
   #ifdef __cplusplus
   extern "C" {

src/free.c

@@ -340,7 +340,10 @@ mi_decl_nodiscard size_t mi_usable_size(const void* p) mi_attr_noexcept {
 
 void mi_free_size(void* p, size_t size) mi_attr_noexcept {
   MI_UNUSED_RELEASE(size);
-  mi_assert(p == NULL || size <= _mi_usable_size(p,"mi_free_size"));
+  #if MI_DEBUG
+  const size_t available = _mi_usable_size(p,"mi_free_size");
+  mi_assert(p == NULL || size <= available || available == 0 /* invalid pointer */ );
+  #endif
   mi_free(p);
 }