automake sometimes do not generate correct macros - force it

cups.spec

@@ -15,7 +15,7 @@ Summary: CUPS printing system
 Name: cups
 Epoch: 1
 Version: 2.2.6
-Release: 30%{?dist}
+Release: 31%{?dist}
 License: GPLv2
 Url: http://www.cups.org/
 Source0: https://github.com/apple/cups/releases/download/v%{VERSION}/cups-%{VERSION}-source.tar.gz
@@ -331,7 +331,7 @@ iconv -f MACINTOSH -t UTF-8 "$f"~ > "$f"
 rm -f "$f"~
 
 aclocal -I config-scripts
-autoconf -I config-scripts
+autoconf -f -I config-scripts
 
 %build
 # add Fedora specific flags to DSOFLAGS
@@ -712,6 +712,9 @@ rm -f %{cups_serverbin}/backend/smb
 %{_mandir}/man5/ipptoolfile.5.gz
 
 %changelog
+* Tue Feb 19 2019 Zdenek Dohnal <zdohnal@redhat.com> - 1:2.2.6-31
+- automake sometimes do not generate correct macros - force it
+
 * Fri Dec 14 2018 Zdenek Dohnal <zdohnal@redhat.com> - 1:2.2.6-30
 - previous commit - fix for previous releases