small proposal: pg_config record flag variables?

Currently, pg_config will tell about the configure options that were
used, but it does not let you find out if any environment variables were
used to determine CC, CFLAGS, etc.  More than once I've found myself
wanting to verify that information about an installation.  So I'm
considering adding options to pg_config to record the more interesting
Makefile variables:
pg_config --ccpg_config --cppflagspg_config --cflagspg_config --cflags_slpg_config --ldflagspg_config
--ldflags_slpg_config--libs
 

Comments?  Are these option names okay, or do they need to be more
verbose?  Any other settings worth recording?
        regards, tom lane