http://berklix.com/~jhs/src/bsd/fixes/FreeBSD/ports/gen/graphics/dri/Makefile.REL=10.1-RELEASE.diff

graphics/dri is in 10.3-RELEASE
graphics/dri not in 10.3-p11 on host=land, or current-2017-09-19

*** 10.2-RELEASE/ports/graphics/dri/Makefile.o	Tue Jan 26 02:49:34 2016
--- new-generic/ports/graphics/dri/Makefile	Tue Jan 26 02:51:13 2016
***************
*** 18,23 ****
--- 18,30 ----
  .if defined(JAPANESE_EXMH)
  RUN_DEPENDS=	wish8.0jp:${PORTSDIR}/japanese/tk80
  BUILD_DEPENDS=	tclsh8.0jp:${PORTSDIR}/japanese/tcl80
+ BUILD_DEPENDS+= ${PORTSDIR}/textproc/py-libxml2
+ # To avoid error:
+ #     checking python2 module: libxml2... no
+ #     configure: error: failed to find required module libxml2
+ #     ===>  Script "configure" failed unexpectedly.
+ #     Please report the problem to x11@FreeBSD.org [maintainer] and attach the
+ 
  WISH=		wish8.0jp
  TCLSH=		tclsh8.0jp
  .else

Ah, Yes ! Thanks.  So
        BUILD_DEPENDS+= ${PORTSDIR}/textproc/py-libxml2
would suffice, but maybe it should be longer ? maybe similar to
        BUILD_DEPENDS+= \
        lib/python2.7/site-packages/libxml2mod.so:\
        ${PORTSDIR}/textproc/py-libxml2
I tried to find what that something should be, by doing 
        cd /usr/ports/textproc/py-libxml2; make clean ; make deinstall
        cd /usr/ports/graphics/dri; make clean; make 
But I failed to find whatever it was,  so not sure if BUILD_DEPENDS 
is needed, or if it was just some local aberation here.

PS Apologies for truncated "Subject: patch for"
instead of "Subject: patch for graphics/dri/Makefile"