Enforce a standard header file guard symbol name

Require that all headers are guarded by a symbol named

  LIBVIRT_$FILENAME

where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.

Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

tests/testutils.h

@@ -20,8 +20,8 @@
  * Karel Zak <kzak@redhat.com>
  */
 
-#ifndef __VIR_TEST_UTILS_H__
-# define __VIR_TEST_UTILS_H__
+#ifndef LIBVIRT_TESTUTILS_H
+# define LIBVIRT_TESTUTILS_H
 
 # include "viralloc.h"
 # include "virfile.h"
@@ -166,4 +166,4 @@ int testCompareDomXML2XMLFiles(virCapsPtr caps,
                                unsigned int parseFlags,
                                testCompareDomXML2XMLResult expectResult);
 
-#endif /* __VIR_TEST_UTILS_H__ */
+#endif /* LIBVIRT_TESTUTILS_H */