move math routines from package sys to package math,
though they still build in src/runtime.

use cgo instead of hand-written wrappers.

R=r
DELTA=740  (289 added, 300 deleted, 151 changed)
OCL=23326
CL=23331
28 files changed
tree: ece2442553c8681e8134d2201e6201e1e429adb8
  1. doc/
  2. include/
  3. lib/
  4. pkg/
  5. src/
  6. test/
  7. usr/