[master] 7f8ac60a5 build: Polish output for the vrt_test.c target

[Dridi Boukelmoune]

commit 7f8ac60a5865cf9171d83e451e3f4de0b4ce9f1f
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Thu Aug 12 10:32:46 2021 +0200

    build: Polish output for the vrt_test.c target

diff --git a/include/Makefile.am b/include/Makefile.am
index 16c63062e..d6afb0438 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -162,7 +162,7 @@ noinst_PROGRAMS = vbm_test vrt_test
 vbm_test_SOURCES = vbm_test.c vbm.h
 
 vrt_test.c: vdef.h vrt.h
-	cat $(srcdir)/vdef.h $(srcdir)/vrt.h > $@
+	$(AM_V_GEN) cat $(srcdir)/vdef.h $(srcdir)/vrt.h > $@
 
 vrt_test_BUILT_SOURCES = vrt_test.c
 vrt_test_CFLAGS = -c