src/cairo.[ch] src/cairo-matrix.c: Add some inline docs for arcs and matrices.
gtk-doc.m4 acinclude.m4: Check in files from gtk-doc to make the dependency on gtk-doc optional.
Add --enable-gtk-doc to the default args.
Don't AC_SUBST a dozen different FOO_CFLAGS and FOO_LIBS. Instead, incrementally build up just CAIRO_CFLAGS and CAIRO_LIBS.
Don't list flags that should get picked up via dependency information through Requires.
Add description of move_to_show_surface.