Fixing OSX makefile

[fgb]

I updated a couple of links for fetch and added some stray files to clean. I'm also making a couple of suggestions regarding requiring PYVERSION in the command line and dropping the PREFIX from mpl_install. For this last one, I'm assuming that the dependencies are compile-time and matplotlib will work correctly from the relevant site-packages (I haven't seen any problems yet, although I've kept the dependencies in the PREFIX), but I welcome any comments or corrections.

[jkseppan]

The brackets that mean optional settings could be mistaken for syntax. I suggest reformulating this along these lines (note that you can set variables on the make command line):

make -f make.osx fetch deps mpl_install PREFIX=/Users/jdhunter/dev PYVERSION=2.6

Variables:
    PREFIX (required): where to install the dependencies
    PYVERSION (optional): <<<please describe the effect and the default>>>

The Python libraries will be installed in the usual location, not under PREFIX.

[fgb]

Thanks for the tip. I was just following standard man notation, but I understand your concern and added a couple commits to address this.

[jkseppan]

I would still like to get a comment from John Hunter on removing the --prefix argument.

[jkseppan]

Summary of changes in my commit:

• export variables directly from make to avoid shell quoting issues; this includes a fix to ARCH_FLAGS
• add check-prefix helper target to avoid accidentally compiling with -I/include/freetype2 etc
• simplify mpl_build etc, add new targets for different ways of installing
• add help as first target to avoid accidental make clean
• document

I got "make binaries" almost working by disabling wxagg from the setup.cfg file and fudging some version numbers of the generated files. I don't think this review request broke anything there, it's just that my system doesn't have a good version of wxPython.

[jkseppan]

This won't merge cleanly to master. I'll prepare another pull request for that.

[jkseppan]

In the absence of further comments, I'll merge this in.