Fixes and improvements for Makefile.MSVC

This change also fixes that bug that the multiple '/' at the start of
request were not coalesced into one.

Older automake (travis, *cough*) do not support the
AM_EXTRA_RECURSIVE_TARGETS option, this results in invoking "it-local"
directly in the travis script which relies on an implementation detail.

Since the "it" target is only used by the integration-tests directory,
just avoid the recursive targets. The README.rst suggests to enter the
integration-tests directory anyway.

This change allows host pattern in --backend to include '*' to
indicate wildcard match.  The wildcard match is made in suffix match
only.