Make std.math compile on Linux/PPC64.

Adds some constants and moves some code to allow std.math to be
compiled on Linux/PPC64.
Fix big endian version of ripemd.

The upper bound of the array index is obviously wrong.
Merge pull request #1234 from redstar/beripe

Fix big endian version of ripemd.
Merge pull request #1232 from redstar/ppcmath

Make std.math compile on Linux/PPC64.
Fixes Issue 9839 - Select should be able to select symbols.
Merge pull request #1235 from AndrejMitrovic/Fix9839

Issue 9839 - Select should be able to select symbols.