Attempt to resolve ambiguity between #include <config.h> for simgear vs.

flightgear, especially when this occurs in a simgear .hxx file.  This is
now expressly forbidden, and will cause problems anyways because we now
changed the name to <simgear_config.h> which isn't installed, so you can't
include it in an installed header file.

simgear/xml/easyxml.cxx

@@ -1,9 +1,5 @@
 // easyxml.cxx - implementation of EasyXML interfaces.
 
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
-
 #include <simgear/compiler.h>
 
 #include <string.h>		// strcmp()

simgear/xml/easyxml.hxx

@@ -8,10 +8,6 @@
 #ifndef __EASYXML_HXX
 #define __EASYXML_HXX
 
-#ifdef HAVE_CONFIG_H
-#  include <config.h>
-#endif
-
 #include <simgear/compiler.h>
 
 #include STL_IOSTREAM