Support LIBS like LDFLAGS.

- Add LIBS="${LIBS}" to MAKE_ENV and CONFIGURE_ENV.
- Add an option helper for LIBS.
- Adjust all ports that already use LIBS.  Also remove references to
  PTHREAD_CFLAGS and PTHREAD_LIBS while here.
- Some ports did not support having a LIBS environment variable and
  required additional patches.

Somewhat simplified a linker command line looks like:

${CC} ${src_LDFLAGS} ${LDFLAGS} ${src_LIBS} ${LIBS}

where src_LDFLAGS and src_LIBS are controlled by upstream and LDFLAGS and
LIBS can be controlled by us.  If possible -L and -l flags need to be
added to LIBS to make sure they appear after any -L and -l flags set by
upstream.  Many ports currently add -L${LOCALBASE}/lib to LDFLAGS but this
may appear too early on the command line causing installed libraries to
be linked in instead of freshly built ones.

Additional changes:
benchmarks/netio: Replace WITH_IPV6 with an IPV6 option.
comms/gnokii: Replace some patches with USES=pathfix.  Also remove -fPIC.
graphics/gimageview: USES=libtool and install desktop file in DESKTOPDIR.
graphics/visionworkbench: Remove FreeBSD 7 support.
multimedia/libmovtar: New LIB_DEPENDS syntax.
multimedia/opencinematools: Use standard do-build.
net/siproxd: USES=libtool:keepla (port actually needs .la files for plugins)
net-mgmt/nagios: Remove -fPIC.
net-mgmt/nagios4: Remove -fPIC.
print/cups-base: Only add -lssp_nonshared on i386 and OSVERSION < 1000036.
security/p11-kit: Replace PTHREAD_LIBS in CONFIGURE_ENV with
ac_cv_func_pthread_mutexattr_init=no in CONFIGURE_ARGS.  This skips a test
in configure that falsely detects pthread_mutexattr_init in our libc.
sysutils/dar: Fix iconv detection.
x11/rxvt-unicode: Remove -lstdc++ and patch configure to remove a FreeBSD
hack and use $CXX as linker as on other platforms.

PR:		190592
Exp-run by:	antoine
Approved by:	portmgr (antoine)


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@357486 35697150-7ecd-e111-bb59-0022644237b5
Fix build for FreeBSD < 9 where libstatgrab 0.90 codepath is used.

PR:		190718
Submitted by:	Kevin Bowling [patch]
Approved by:	maintainer


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@360770 35697150-7ecd-e111-bb59-0022644237b5
- Convert net/librouteros to USES=libtool and bump dependent ports
- USES=tar:bzip2
- Add INSTALL_TARGET=install-strip


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@361450 35697150-7ecd-e111-bb59-0022644237b5
- Update libstatgrab to 0.91.
- Bump revision on dependent ports to chase shlib bump.


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@361588 35697150-7ecd-e111-bb59-0022644237b5
Clean up databases/rrdtool

Change library dependensies to use USES= where applicable.
Build ports documentation and examples, depending on respective option.
Add two new options, NLS and GRAPH, the GRAPH option enables the rrdtool graph
command, which pulls in cario and a lot of other dependencies.  [1]
Add missing dependencies.
Becase of shlib version bump, bump portrevision on depending ports.

PR:		192024 [1] (based on)
Submitted by:	asomers
Approved by:	portmgr (blanket, portrevision bumps)


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@362726 35697150-7ecd-e111-bb59-0022644237b5
Bump PORTREVISION on more ports that depend on libgcrypt after the update
in r363436 and remove the UPDATING entry because it did not guarantee
that all ports were updated nor that they were updated in the right order.
Also remove libgcrypt.la again.

PR:		192342
Approved by:	portmgr (implicit, bump unstaged ports)


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@364143 35697150-7ecd-e111-bb59-0022644237b5
- Unbreak the build, if the PYTHON option is selected (caused by the
  lang/python27 update in r363790)

Reported by:	robak@
With hat:	python@


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@364305 35697150-7ecd-e111-bb59-0022644237b5
- Switch comms/libmodbus to USES=libtool, drop .la files
- Bump dependent ports as .so version has changed

Approved by:	portmgr blanket


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@365006 35697150-7ecd-e111-bb59-0022644237b5
devel/protobuf-c: update to 1.0.1

- Bump port revision due to shlib change
- Add DOCS option
- Pass maintainership to submitter

PR:		192175
Submitted by:	truckman
Approved by:	maintainer


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@365134 35697150-7ecd-e111-bb59-0022644237b5
mail/libesmtp:
- Convert to USES=libtool and bump dependent ports
- Use option helpers
- Remove PTHREAD_CFLAGS and PTHREAD_LIBS
- Add INSTALL_TARGET=install-strip


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@365199 35697150-7ecd-e111-bb59-0022644237b5
- Move RESETPREFIX to default PLIST_SUB

With hat:	portmgr


git-svn-id: http://svn.freebsd.org/ports/head/net-mgmt/collectd5@365325 35697150-7ecd-e111-bb59-0022644237b5