Thus, my proposal is to use MXE for building a new 14.4.1 (or
14.4.1.1, or 14.4.1a) Windows binary that includes flac and sndfile
support; and probably for later releases as well. I could turn
mingwbuild into an mxebuild that automates the build process (for MXE,
then for SoX using MXE). I guess I could also build the whole Windows
package myself, if necessary/preferred by Chris.