portmaster -r png- Stop in /usr/ports/devel/gobject-introspection

[b. f.]

> > /usr/bin/ld: warning: libpng.so.6, needed by /usr/local/lib/libcairo.so, not
> > found (try using -rpath or -rpath-link)
> > /libexec/ld-elf.so.1: Shared object "libpng.so.6" not found, required by
> > "libcairo.so.2"
> > Command
> > '['/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8/tests/scanner/tmp-introspectyVPLgw/Regress-1.0',
> > '--introspect-dump=/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8/tests/scanner/tmp-introspectyVPLgw/types.txt,/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8/tests/scanner/tmp-introspectyVPLgw/dump.xml']'
> > returned non-zero exit status 1
> > gmake[4]: *** [Regress-1.0.gir] Fel 1
> > gmake[4]: Lämnar katalogen
> > "/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8/tests/scanner"
> > gmake[3]: *** [all-recursive] Fel 1
> > gmake[3]: Lämnar katalogen
> > "/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8/tests"
> > gmake[2]: *** [all] Fel 2
> > gmake[2]: Lämnar katalogen
> > "/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8/tests"
> > gmake[1]: *** [all-recursive] Fel 1
> > gmake[1]: Lämnar katalogen
> > "/usr/ports/devel/gobject-introspection/work/gobject-introspection-0.10.8"
> > gmake: *** [all] Fel 2
> > *** Error code 1
>
> According to the message, libcairo.so.s is linked to libpng.so.6 which
> is now obsolete. Looks like cairo has not been rebuilt for some
> reason. Do you have /var/db/pkg/cairo-*/+IGNOREME? The problem with
> cairo 1.10.2 appears to now be fixed, so you should be able to upgrade
> it if that is why it did not get updated.

If he used the commands as he described, then portmaster should
ultimately have updated cairo.  But since the gobject-introspection
port doesn't depend upon cairo, at least according to the makefiles in
Ports, there was no reason for portmaster to update cairo _before_
updating gobject-introspection.  portmaster cannot anticipate that the
gobject-introspection build can be affected by the presence of another
port that is supposedly unrelated, and many such problems are not
uncovered by the routine testing that is conducted with sandboxed
builds. That is why one-port-at-a-time, un-sandboxed, "in-place"
updates are risky, especially for major updates (that is mentioned
near the bottom of the portmaster manpage, although not in so many
words), even though many people find them to be convenient.

b.