code duplication: parsing arguments vs. environment variables

[Jeff Johnson]

Right now, lsbcc parses several options twice: once when specified via
environment variable, and then again when specified via the command line. This
results in behavior where some options act differently when passed one way or
the other.

For example:

$ LSB_MODULES=Toolkit_Qt3 ./lsbcc -c -o foo.o lsbcc.c
$ ./lsbcc --lsb-modules=Toolkit_Qt3 -c -o foo.o lsbcc.c
unknown module: Toolkit_Qt3
Usage ./lsbcc:
[...]

The bugfix (for bug 2004, as far as I can tell) got applied in one place, but
not the other.

I propose that the command-line options should modify the environment, and then
the environment should be parsed exactly once.