RFE: dev env should provide path queries

In several places, LSB builds are so wired in to the layout that LSB-provided
tools assume that they can't build if the tools are elsewhere. The most
persistent offender is the desktop-related builds, including the test suite and
appbat where some pkg-config trickery is used, and the build starts with a
define of PKG_CONFIG_PATH to /opt/lsb/lib/pkgconfig (lib64 on 64-bit). If a
distro has packaged the tools they're supposed to put them in /usr, and this
will fail completely. See bug 1535 for another example.

Proposal: lsbcc now has a variety of path-setting options to augment the older
environment variables. These options could be used as a template for new query
options, in other words:

lsbcc --lsb-libpath=<lsb_lib_path> sets the path to find the stub libraries

lsbcc --query-lsb-libpath could return the built-in path

This would allow constructs like this:

PKG_CONFIG_PATH=`lsbcc --query-lsb-libpath`/pkgconfig

Query options would have to turn off further lsbcc processing and just return
the information.