Added note about path for flex and bison

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@15640 c8812cc2-4d05-0410-92ff-de0c093fc19c

INSTALL

@@ -1,7 +1,7 @@
 Quantum GIS (QGIS)
 Building QGIS from source - step by step
 
-Last update: 20110328
+Last update: 20110329
 Last change: 20110307
 
   1. Introduction
@@ -755,6 +755,9 @@ the top level QGIS directory.
 In the Where to build the binaries: box, browse to the 'build' directory you
 created.
 
+Adjust the path to bison and flex so that the shortened C:/Progra~1 is used 
+rather than C:/Program Files.
+
 Hit Configure to start the configuration and select Visual Studio 9 2008
 and keep native compilers and click Finish.