[Ltib] How to handle incorrect -config files

[Mike Goins]

libxml2 build generates a $DEV_IMAGE/bin/xml2-config file that is used
by other libs that depend on libxml2, but the file has a host absolute
entry ( prefix=/usr ) which appears in "xml2-config --libs" output.  I
think this may throw off the other libs.   What is the best way to
"fix" these types of config file?   "Massage" correct values into them
by the owning package.  In this case libxml2.spec sed's the file?