maintainer-feedback requested: [Bug 262613] textproc/libxml2: icu support

Bugzilla Automation <bugzilla@FreeBSD.org> has asked freebsd-desktop (Team)
<desktop@FreeBSD.org> for maintainer-feedback:
Bug 262613: textproc/libxml2: icu support
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=262613



--- Description ---
libxml2 can be can be configured to use icu. 

This support for icu may be used for some purposes of testing in
www/qt5-webengine builds, under the qmake configure arg `-webengine-icu'.
Albeit, this support might need some additional patching for it to be of use
there.	Perhaps it could also be of some use in other codebases.

This patch will enable the '--with-icu' configure arg for libxml2, furthermore
adding icu as a library dependency for libxml2 and adding a cflag for the icu
includes. This patch also updates the libxml2 *.pc file to ensure that an
include path for the how the icu includes files would usually be referenced
will be added to cflags in builds for dependendent packages. This would
normally add -I/usr/local/include to cflags.