glcpp: Add a newline to expanded #line directives.

glcpp: Add a newline to expanded #line directives.

Otherwise, the preprocessor happily outputs

    #line 2 4 <your next line of code>

and the main compiler gets horribly confused and fails to compile.

This is not the right solution (line numbers in error messages will
likely be off-by-one in certain circumstances), but until Carl comes
up with a proper fix, this gets programs running again.

Fixes regressions in Regnum Online, Overgrowth, Piglit, and others since
commit aac78ce8234d96932c38b3f48b1d828077bc0027.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51802
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=51506
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41152
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>