so it's part of the distribution (manual.texi includes this file)
It will be replaced with the correct one from the mysqldoc tree before
building the distribution
- removed generation and inclusion of MIRRORS file, since the mirror list
is no longer part of manual.texi anyway
- replaced YFLAGS with AM_YFLAGS in sql/Makefile.am to make automake happy
- Redirect standard error when checking for dpkg-architecture in ltconfig
to avoid error message showing during configuration
