build: fix distcheck

[Akim Demaille]

In maint and master.

commit 2c819119cde00c2279c21eacee65450d3f63552a
Author: Akim Demaille <address@hidden>
Date:   Sun Sep 8 18:48:49 2019 +0200

    build: fix distcheck
    
    * configure.ac (gl_LIBOBJS): Adjust so that the generated files are
    indeed the expected ones.

diff --git a/configure.ac b/configure.ac
index 83e2c972..523bd331 100644
--- a/configure.ac
+++ b/configure.ac
@@ -297,4 +297,12 @@ AC_SUBST([GCC])
 AC_CONFIG_FILES([Makefile
                  po/Makefile.in
                  doc/yacc.1])
+
+# Fix LIBOBJS to give the Makefile the right file names.  Otherwise
+# compilation works, but with unexpected file names, so clean rules don't
+# remove the actual files and distcheck fails.
+AC_CONFIG_COMMANDS_PRE([
+  gl_LIBOBJS=`echo "$gl_LIBOBJS" | sed -e 's, lib/, lib/libbison_a-,g'`
+])
+
 AC_OUTPUT