Merge branch 'js/mingw-no-nedmalloc' into maint-2.54

Stop using unmaintained custom allocator in Windows build which was the last user of the code. * js/mingw-no-nedmalloc: mingw: remove the vendored compat/nedmalloc/ subtree mingw: drop the build-system plumbing for nedmalloc mingw: stop using nedmalloc