graphics/libemf: update to 1.0.13 release
This update fixes a number of vulnerabilities:
CVE-2020-13999 (fixed in 1.0.13)
CVE-2020-11863 (fixed in 1.0.12)
CVE-2020-11864 (fixed in 1.0.12)
CVE-2020-11865 (fixed in 1.0.12)
CVE-2020-11866 (fixed in 1.0.12)
Add a new port graphics/libEMF.
This is a C/C++ library which provides a drawing toolkit
based on ECMA-234. The general purpose of this library is
to create vector graphics files on POSIX systems which can
be imported into StarOffice/OpenOffice.