Add support for --enable-relocatable in mingw builds on Cygwin hosts.

Reported by Michele Locati <michele@locati.it> in
<https://github.com/mlocati/gettext-iconv-windows/pull/47#issuecomment-3041406917>.

* configure.ac: Invoke gl_BUILD_TO_HOST_BINDIR.
* src/Makefile.in (bindir_c_make, localedir_c_make): New variables.
(iconv_no_i18n.@OBJEXT@, iconv.@OBJEXT@): Fix value of INSTALLDIR and
LOCALEDIR.
3 files changed