pkgconfig: fix parsing default search path

pkg-config 0.29 reports the scanning directory differently:

Scanning directory #3 '/usr/local/lib/pkgconfig'
instead of
Scanning directory '/usr/local/lib/pkgconfig'

Author: Alexander Duda

lib/utilrb/pkgconfig.rb

@@ -461,7 +461,7 @@ def self.each_package(regex = nil)
         end
 
 
-        FOUND_PATH_RX = /Scanning directory '(.*\/)((?:lib|lib64|share)\/.*)'$/
+        FOUND_PATH_RX = /Scanning directory #?\d? '(.*\/)((?:lib|lib64|share)\/.*)'$/
         NONEXISTENT_PATH_RX = /Cannot open directory '.*\/((?:lib|lib64|share)\/.*)' in package search path:.*/
 
         # Returns the system-wide search path that is embedded in pkg-config