[FYI] tests: fix spurious failure in test on TEXINFO_TEX overriding

* t/txinfo-override-texinfo-tex.sh: Here.  The issue was pre-existing, but
has been only recently exposed by the fix for automake bug#18286 "distcheck
fails to detect missing files" (see commit v1.14.1-4-g01a7a4a) and by the
BSD make semantics.  To convince yourself this change actually makes sense
semantically, see https://sourceware.org/ml/binutils/2012-06/msg00004.html

Signed-off-by: Stefano Lattarini <[email protected]>
---
 t/txinfo-override-texinfo-tex.sh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/t/txinfo-override-texinfo-tex.sh b/t/txinfo-override-texinfo-tex.sh
index 72bf834..c03dd39 100644
--- a/t/txinfo-override-texinfo-tex.sh
+++ b/t/txinfo-override-texinfo-tex.sh
@@ -30,12 +30,13 @@ AC_OUTPUT
 END
 
 cat > Makefile.am << 'END'
-TEXINFO_TEX = $(srcdir)/tex/texinfo.tex
+TEXINFO_TEX = ../tex/texinfo.tex
 info_TEXINFOS = main.texi
 sure_it_exists:
-	test -f $(TEXINFO_TEX)
+	test -f $(srcdir)/$(TEXINFO_TEX)
 sure_it_is_not_distributed: distdir
 	test ! -f $(distdir)/tex/texinfo.tex
+check-local: sure_it_exists
 END
 
 cat > main.texi << 'END'
@@ -61,7 +62,6 @@ test -f tex/texinfo.tex
 
 ./configure
 
-$MAKE sure_it_exists
 $MAKE distcheck
 $MAKE sure_it_is_not_distributed
 
-- 
2.1.3