[ng] header vars: move check for GNU make version earlier

* lib/am/header-vars.am: Move the check that the version of GNU make
in use is modern enough before everything else.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --git a/lib/am/header-vars.am b/lib/am/header-vars.am
index de266d8229c4205b9f883b0bc9ec5f4ab7ac8820..d69ad3a0488748ba96b8256613d3de45acd407fe 100644 (file)
--- a/lib/am/header-vars.am
+++ b/lib/am/header-vars.am
@@ -14,6 +14,14 @@
 ## You should have received a copy of the GNU General Public License
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+## Makefiles generated by Automake-NG require GNU make >= 3.81.
+## The .FEATURES special variable has been introduced in that make
+## version, so use it as a witness to determine whether the current
+## make is good enough.
+ifndef .FEATURES
+  $(error Automake-NG based builds require GNU make 3.81 or later)
+endif
+
 VPATH = @srcdir@
 
 ## Enhance performance by removing GNU make builtin rules that would be
@@ -62,14 +70,6 @@ define am.chars.newline
 $(am.chars.empty)
 endef
 
-## Makefiles generated by Automake-NG require GNU make >= 3.81.
-## The .FEATURES special variable has been introduced in that make
-## version, so use it as a witness to determine whether the current
-## make is good enough.
-ifndef .FEATURES
-  $(error Automake-NG based builds require GNU make 3.81 or later)
-endif
-
 ## Neutralize unwarranted environment settings that might interfere with
 ## our Makefiles.
 ifdef SUBDIRS