include: Switch to #pragma once pattern

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/core/crcXXgen.h.tpl b/include/osmocom/core/crcXXgen.h.tpl
index a931bc3..164f720 100644
--- a/include/osmocom/core/crcXXgen.h.tpl
+++ b/include/osmocom/core/crcXXgen.h.tpl
@@ -20,8 +20,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef __OSMO_CRCXXGEN_H__
-#define __OSMO_CRCXXGEN_H__
+#pragma once
 
 /*! \addtogroup crcgen
  *  @{
@@ -54,6 +53,4 @@
 
 /*! @} */
 
-#endif /* __OSMO_CRCXXGEN_H__ */
-
 /* vim: set syntax=c: */