1.5.0: API documentation is not installed

When FLAC 1.5.0 is built with GNU autotools, the API documentation
that is included in the release tarball is not installed.

This is due to this check in configure.ac:

  if test ! -n "$DOXYGEN" && test -f "$srcdir/doc/FLAC.tag" && test -f "$srcdir/doc/api/modules.html" ; then
          HAS_PREBUILT_DOXYGEN=yes
  fi
  AM_CONDITIONAL(FLaC__HAS_PREBUILT_DOXYGEN, test "x$HAS_PREBUILT_DOXYGEN" = xyes)

There is no file doc/api/modules.html.  Has something changed with
doxygen?

-- 
Christian "naddy" Weisgerber                          [email protected]