build-mingw-w64, build-busybox: Bump to a newer version

This version of mingw-w64 includes the function "mkdtemp", which
breaks building the previously pinned version of busybox-w32 on i686.

Update both projects in sync, so that builds with newer nightly
versions of mingw-w64 also succeed.

build-busybox.sh

@@ -16,7 +16,7 @@
 
 set -e
 
-: ${BUSYBOX_VERSION:=90c68f18dc24fb3919811199f849fa2dc7a75294}
+: ${BUSYBOX_VERSION:=1f493261d16be3d984fe8a689f5113dafb6eaaa7}
 
 BUILDDIR=build