Portability fixes:
* clutter/clutter-private.h:
Bracket #include "unistd.h" with #ifdef HAVE_UNISTD_H
* clutter/clutter-fixed.c:
Use "", not <> for inclusion of local files.
(clutter_sqrtx): forward declare local variables.
* clutter/clutter-debug.h:
Added non-gcc (c99) implementation of variadic debug macros for
when not compiling with gcc.
* clutter/pango/pangoclutter-render.c:
Fixed some strange uses of CLUTTER_NOTE() + stripped trailing
whitespace.