Compiling R and packages with debug information?

In Unix/Linux/Macos, how do I compile R or a package with debug
information?  In Windows it's done by defining a DEBUG environment
variable, but I don't see support for that in the Unix makefiles.  Is
there a standard ./configure option to set this?

It is on by default, but controlled by setting CFLAGS/FFLAGS/CXXFLAGS
(which contain -g by default).

The reason the default is different is that we presume that a Unix-alike 
comes with a usable debugger (you may disagree, and it may not be true) 
and Windows does not (definitely an extra).

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595