NonRecursiveMakefile

Proposal:

 Switch to a single makefile in src/ that includes all the
 stuff previously in src/**/Makefile.am.

 Top-level makefile continues to be recursive make.  This simplifies
 data installation, and the benefits of changing aren't much for
 directories outside of src/**.

 Use automake's `include' directive on blah/Makefile_insert.

 Most existing blah/Makefile.am content goes to blah/Makefile_insert,
 e.g. blah_libblah_a_{CPPFLAGS,SOURCES,LDFLAGS,LDADD}.

 Some "global" variable definitions move to src/Makefile.am:
 noinst_LIBRARIES, DISTCLEANFILES, EXTRA_DIST, EXTRA_PROGRAMS,
 TESTS, check_PROGRAMS.

 INCLUDES/AM_CPPFLAGS become e.g. blah_libblah_a_CPPFLAGS (i.e.
 per-target instead of per-directory).

 "Local" variable definitions (e.g. used for conditional compilation,
 e.g. win32_sources) go in src/blah/Makefile_insert, and acquire a `blah_'
 prefix.  (The win32_sources variable from src/Makefile.am goes to
 src/Makefile_insert with no added prefix.)

 src/Makefile.am contains:

     include blah/Makefile_insert

     Definitions for the aforementioned "global" variables.

     dist-hook rule.

Advantages:

   Can depend on things from other directories.  E.g. some files in
   display/ depend on helper/sp-marshal.h having been built, and various
   */*-test programs depend on libraries in other directories (previously
   hacked with a `check-recursive: all-recursive' dependency in
   src/Makefile.am).

   Compilation is expected to be faster:

     - Fewer invocations of automake and make.

     - Better parallelization is possible with make -j / make -l (e.g.
       when using distcc).

   However, making CPPFLAGS per-target means much longer generated
   Makefile content.  I haven't yet done timing tests (underway).

Disadvantages:

   All files mentioned in the makefile fragments need to specify their
   directory.  E.g. if blah/Makefile.am used to contain

     libblah_a_SOURCES = \
       foo.cpp foo.h

   then blah/Makefile_insert will now contain

     blah_libblah_a_SOURCES =  \
       blah/foo.cpp    \
       blah/foo.h

Any other advantages/disadvantages?

Checks to be done before switching:

   `make install' creates same directory tree.

   - Done.  Some differences in the inkscape/inkview executable files,
     all other files bytewise-identical.

   `make check' works.

   - Done.  Works.  Hmm, haven't checked that all expected checks are
     getting run.

   `make check' works immediately after `make clean'.

   - Not yet checked.

   `make distcheck' works.

   - Not yet checked.

Any other checks to be done?

pjrm.