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/viriscsitest.c

@@ -27,8 +27,7 @@ main(void)
     return EXIT_AM_SKIP;
 }
 #else
-# define __VIR_COMMAND_PRIV_H_ALLOW__
-
+# define LIBVIRT_VIRCOMMANDPRIV_H_ALLOW
 # include "vircommandpriv.h"
 # include "viriscsi.h"