This begins to decouple the rater directory conventions using an incremental
approach, defaulting to the existing structure. Not all things were
modified (for example, cleaning will not work properly with a custom
SRCPATHS if those directories do not exist); WIP.
* build-aux/Makefile.am (path_dsl): Use `CALCROOT'.
(suppliers.mk): Test for existence of program.dep and c1map directory
before acting on them.
* build-aux/m4/calcdsl.m4: Default SRCPATHS. Output it during configure.
Expose CALCROOT and SRCPATHS using AC_SUBST.
Invoke suppmk-gen using SRCPATHS.
* build-aux/suppmk-gen: Use arguments (SRCPATHS) in place of hard-coded paths.