Backport the CMAKE related changesets from the main branch

[e20fecd1945f] Add check target for CMake (#388)
[e74b5db4f2c6] Put the output of chg-len.py in the version string (#389)
[7d166b8b8018] Safer call of ./scripts/chg-len.py on Windows (#389)
[659ba4805a48] Make CMAKE config more consistent with configure.ac (#390)
[63e4468c680e] Add 'Maintainer' CMAKE build type (#388, #390)
[a725503acfe9] Allow CPACK configuration on all platforms
[10242c611190] Create and install lemon.pc (#393)
[48e29534cf03] The deafult target doesn't build lp_test and mip_test (#388)
[0fbbdd578c06] Full path for DoxygenLayout.xml in Doxyfile.in (#395)
[481496e6d71f] SOURCE_BROWSER Doxygen switch is configurable from CMAKE (#395)
[09282720100b] update-external-tags CMAKE target (#395)

#! /usr/bin/env python

import sys

from mercurial import ui, hg

from mercurial import util

util.rcpath = lambda : []

if len(sys.argv)>1 and sys.argv[1] in ["-h","--help"]:

    print """

This utility just prints the length of the longest path

in the revision graph from revison 0 to the current one.

"""

    exit(0)

u = ui.ui()

r = hg.repository(u, ".")

N = r.changectx(".").rev()

lengths=[0]*(N+1)

for i in range(N+1):

    p=r.changectx(i).parents()

    if p[0]:

        p0=lengths[p[0].rev()]

    else:

        p0=-1

    if len(p)>1 and p[1]:

        p1=lengths[p[1].rev()]

    else:

        p1=-1

    lengths[i]=max(p0,p1)+1

print lengths[N]