[petsc-dev] Experimental GNU make build system

[Jed Brown]

I just merged 'jed/gnumake' to 'next'.  I haven't added support for
static libraries yet, but it should work with pretty much all other
configurations using compilers that support '-MMD -MP' (tested with gcc,
clang, and intel; C, C++, and Fortran; single and multiple library).

  $ make -f gmakefile -j20 PETSC_ARCH=your-choice

The makefile is 100 lines and the Python for figuring out what to
include in the build is about the same (conf/gmakegen.py; neglecting
python-2.4 compatibility stuff).  Simplifying the rules would reduce
that, naturally.

Let me know how it works for you.