[master] 4e0af4904 build: Make the fake linker produce a target

[Dridi Boukelmoune]

commit 4e0af4904de07ca51fdec7494bbc7060a2dd0743
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Fri Aug 20 13:42:21 2021 +0200

    build: Make the fake linker produce a target
    
    Otherwise we always try to rebuild vrt_test when running make.

diff --git a/include/Makefile.am b/include/Makefile.am
index d6afb0438..d5c5925c5 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -166,6 +166,6 @@ vrt_test.c: vdef.h vrt.h
 
 vrt_test_BUILT_SOURCES = vrt_test.c
 vrt_test_CFLAGS = -c
-vrt_test_LINK = :
+vrt_test_LINK = cat >$@
 
 TESTS = vbm_test