Fix compilation with -stdc=c11

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26231 f0d54148-0727-0410-94bb-9a71ac55c965
Fix warning with -stdc=c11 (strcasecmp() needs include <strings.h>)

git-svn-id: https://svn.osgeo.org/gdal/trunk/gdal@26232 f0d54148-0727-0410-94bb-9a71ac55c965