How hard would it be to implement --enable-debug=module1, module2, ... ?

It is often very useful to build just some modules with debugging
information. (Because building large amounts of code you are not going
to be debugging anyway might take lots of disk space, slow down
linking, etc.)

Currently that has to be done "manually". For temporary debugging
needs local to one module, that's OK.

But for more permanent debugging needs  concentrated to either one
high-level aspect (Calc, Writer, Impress) or to low-level stuff (sal,
cppu, bridges, etc) it would be nice to be able to specify which
modules to build for debugging on the configure command line (read: in
your autogen.lastrun).

For dmake-based modules, I guess it would be relatively trivial to
implement as build.pl is invoked separately for each module and can
check whenther the module name is included in a DEBUG_MODULES env var
that has a value like "sal,cppu,cppuhelper", or something like that.
But dmake-based modules are getting rare, and for instance none of the
examples mentioned above is dmake-based.

For gbuild-based modules it might be harder, as the point of gbuild is
to have just one make process, and there is one global gb_DEBUGLEVEL
variable set in gbuild.mk. Anybody have good ideas?

--tml