[gtk-doc] configure: fix typo

[Stefan Kost <stefkost src gnome org>]

commit 477fbbc38cc7da8fd0573ba15afe0db5f2ee0ccf
Author: Stefan Sauer <ensonic users sf net>
Date:   Tue Jul 19 21:39:13 2016 +0200

    configure: fix typo

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7dfae29..ee4d651 100644
--- a/configure.ac
+++ b/configure.ac
@@ -172,7 +172,7 @@ PKG_CHECK_MODULES(TEST_DEPS, [glib-2.0 >= 2.6.0 gobject-2.0 >= 2.6.0],
        ]
 )
 AM_CONDITIONAL(GTK_DOC_USE_LIBTOOL, test -n "$LIBTOOL" -a x$gtk_doc_use_libtool = xyes )
-dnl this enable the rule in test/Makefile.am
+dnl this enables the rule in test/Makefile.am
 AM_CONDITIONAL(BUILD_TESTS, test x$build_tests = xyes)
 AC_SUBST(glib_prefix)