* module/system/base/Makefile.am: Add pmatch.scm.
* module/system/base/pmatch.scm: New file, taken from Dan Friedman's
alpha-kanren paper. Implements a less magical match syntax, pmatch.
* module/system/vm/assemble.scm: No more need for (ice-9 match).
* module/system/vm/conv.scm (code-pack, code->object): Change to use
pmatch.
