Solution.pm mistakenly believed that the xml option requires the xslt
option, when actually the dependency is the other way around; and it
believed that libxml requires libiconv, which is not necessarily so,
so we shouldn't enforce it here.  Fix the option cross-checking logic.

Also, since AddProject already takes care of adding libxml and libxslt
include and library dependencies to every project, there's no need
for the custom code that did that in mkvcbuild.  While at it, let's
handle the similar dependencies for uuid in a similar fashion.

Given the lack of field complaints about these overly strict build
dependency requirements, there seems no need for a back-patch.

Michael Paquier

Discussion: <CAB7nPqR0+gpu3mRQvFjf-V-bMxmiSJ6NpTg9_WzVDL+a31cV2g@mail.gmail.com>