pcp updates: configure script

[Nathan Scott <nathans@xxxxxxxxxx>]

Changes committed to git://git.pcp.io/pcp.git master

 configure    |  272 ++++++++++++++++++++++++++++++-----------------------------
 configure.ac |   11 ++
 2 files changed, 152 insertions(+), 131 deletions(-)

commit 1e7698cdd651cf1210013d0e4be9b284d353bdc8
Author: Nathan Scott <nathans@xxxxxxxxxx>
Date:   Fri Apr 10 10:27:00 2015 +1000

    build: add missing configure check for pkg-config requirement
    
    Some folks trying out building PCP for subsequent Vector use have
    reported obscure configure errors when they don't have pkg-config
    installed.  We use this unilaterally now, so we need to check for
    it on the local system before using it.  Make It So.