ensure GEOS includes come at end of CPPFLAGS, not the start or they may override local GDAL include files.  Also some reformatting for neatness.

git-svn-id: https://svn.osgeo.org/gdal/trunk@27284 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_travis_macosx