Convert USE_GNOME=pkgconfig to USES=pkgconfig
While here:
- Trim headers
- Convert:
  * USE_GNOME=gnomehack -> USES=pathfix
  * USE_PERL5 -> USES=perl5
  * USE_GMAKE -> USES=gmake

(cherry picked from commit b5c4dd3fae7295a4bc13a27b98b9a622508f460d)

Conflicts:
	net/mono-zeroconf/Makefile
	net/netatalk3/Makefile
	net/sdl_net/Makefile
Fix build on head with iconv in libc

(cherry picked from commit 131e0f4afb25e1b1cda0fa2ee5d894f875dab3a1)

Conflicts:
	net/netatalk/Makefile
Do not overwrite CONFIGURE_ARGS

Submitted by:	tijl

(cherry picked from commit 5c088cb86d08c638f00b1d6eee561035def5e1b4)
. introduce ICONV_CONFIGURE_BASE variable at Mk/Uses/iconv.mk. It's value is
  "--with-libiconv=${LOCALBASE}" at systems pre OSVERSION 100043 and "" (null)
  otherwise;
. convert all ports which has CONFIGURE_ARGS=--with-libiconv=${LOCALBASE}.

Approved by:	portmgr (bapt, implicit)

(cherry picked from commit d4be7ebb16af8657e516c12bf0574fb925a3f26f)

Conflicts:
	dns/idnkit2/Makefile
	www/dansguardian-devel/Makefile
	www/dansguardian/Makefile
Update to 3.1.0.  See
http://netatalk.sourceforge.net/3.1/ReleaseNotes3.1.0.html for a list of
changes in this release.

Additionally, re-enable mDNSResponder support [1].

Convert to STAGE.

PR:		183601 [1]
Submitted by:	"Bradley T. Hughes" <bradleythughes@fastmail.fm> [1]

(cherry picked from commit fed9899cfc2c31eb0fa429039564c2335604b760)