Log Message:
Update to 0.27 (not using --with-internal-glib yet):

pkg-config 0.27
===

 - Drop usage of popt for equivalent API in glib2.
 - Add back an internal snapshot of glib2 to break circular dependency.
   This can be used by passing --with-internal-glib to configure. On
   Windows it may still be required to use an installed glib.
 - Fix --exists to check for Requires and Requires.private. This ensures
   that all necessary packages are installed prior to using --cflags,
   --libs, etc.
 - Various fixes for MinGW which should allow it to be used unpatched on
   that system.
 - New autoconf macros PKG_INSTALLDIR and PKG_NOARCH_INSTALLDIR to help
   determine the .pc file install directory.
 - Fix handling of --exact/atleast/max-version vs. =/>=/<=.
 - Fix errors in man page source.
 - Ensure testing only searches in the check directory.
 - Bump glib requirement to 2.16 to avoid deprecated
   g_win32_get_package_installation_subdirectory().
 - Autotools refresh and update. The required versions now are
   autoconf-2.62, automake-1.11 and libtool-2.2.
 - Use g_alloca from glib instead of figuring out alloca ourselves.
 - Remove search for setresuid & setreuid only needed for internal popt.
 - Bugs fixed: 833, 2458, 5214, 5326, 5703, 6074, 8653, 9135, 9143,
   9584, 10652, 11464, 14396, 17053, 23922, 28776, 29011, 29801, 31699,
   31700, 32622, 34382, 37266, 39646, 41081, 43149, 44843, 45599, 45742,
   48743