* src/w32heap.c (mmap_alloc): If reserving memory succeeds, but
committing fails, return NULL. Don't call GetLastError twice for
the same API error.
(mmap_realloc): Zero out MEMORY_BASIC_INFORMATION structures
before calling VirtualQuery, to avoid using garbled values if the
call fails. If committing more pages from the same block fails,
fall back on mmap_alloc + CopyMemory. Enhance debugging printouts
if the call to VirtualAlloc to commit more pages fails.
(Bug#22526)