Remove all cygwin CHOST changes

Since #5448 CHOST defaults to cygwin now, so this
is no longer needed.

git/PKGBUILD

@@ -100,9 +100,8 @@ build() {
   export PYTHON_PATH='/usr/bin/python'
   cd "${srcdir}/${pkgname}-${pkgver}"
 
-  local CYGWIN_CHOST="${CHOST/-msys/-cygwin}"
   ./configure \
-    --build=${CYGWIN_CHOST} \
+    --build=${CHOST} \
     --prefix=/usr \
     --sysconfdir=/etc \
     --libexecdir=/usr/lib \