Fix obvious compilation error in sections_solaris.

I stumbled over this while reading the source. Not actually
tested, but should not be worse than the current state.
Merge pull request #518 from klickverbot/solaris-section

Fix obvious compilation error in rt.sections_solaris.
Add in branches of pthread sizes for non-x86 platforms.
$(MODEL_FLAG) not needed for doc and di generation
Add some definitions for ARM
Merge pull request #520 from andralex/less-model

[MINOR] $(MODEL_FLAG) not needed for doc and di generation
Merge pull request #521 from jpf91/fixARM

Add some definitions for ARM
Merge pull request #519 from ibuclaw/dlp64pthread

Add in code paths for pthread sizes on non-x86 platforms.