compiler: Fix C-style comment parsing.
compiler: Fix C-style comment parsing.

The compiler was incorrectly seeing /*/ as a complete C-style
comment.

Fixes #35.

R=iant
CC=gofrontend-dev
https://golang.org/cl/112770045

anlhord/gofrontend,golang/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,golang/gofrontend,qskycolor/gofrontend,golang/gofrontend,qskycolor/gofrontend,anlhord/gofrontend,anlhord/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,qskycolor/gofrontend,anlhord/gofrontend,anlhord/gofrontend,golang/gofrontend,anlhord/gofrontend