Disabling parallel build to avoid build issues with xtables

See http://patchwork.alpinelinux.org/patch/1787/ for reference
This should be fixed in 1.6.1; parallel build can be restored after the
  update

iptables.spec

@@ -7,7 +7,7 @@
 Name: iptables
 Summary: Tools for managing Linux kernel packet filtering capabilities
 Version: 1.6.0
-Release: 3%{?dist}
+Release: 4%{?dist}
 Source: http://www.netfilter.org/projects/iptables/files/%{name}-%{version}.tar.bz2
 Source1: iptables.init
 Source2: iptables-config
@@ -121,7 +121,10 @@ sed -i 's|^runpath_var=LD_RUN_PATH|runpath_var=DIE_RPATH_DIE|g' libtool
 
 rm -f include/linux/types.h
 
-make %{?_smp_mflags}
+# Parallel builds may fail due to xtables-config-parser.h not being generated
+# in time.  See http://patchwork.alpinelinux.org/patch/1787/
+# This should be fixed in 1.6.1
+make
 
 %install
 make install DESTDIR=%{buildroot} 
@@ -285,6 +288,12 @@ done
 %{_sbindir}/xtables-compat-multi
 
 %changelog
+* Thu Feb 02 2017 Petr Šabata <contyk@redhat.com> - 1.6.0-4
+- Disabling parallel build to avoid build issues with xtables
+- See http://patchwork.alpinelinux.org/patch/1787/ for reference
+- This should be fixed in 1.6.1; parallel build can be restored after the
+  update
+
 * Mon Dec 19 2016 Thomas Woerner <twoerner@redhat.com> - 1.6.0-3
 - Dropped bad provides for iptables in services sub package (RHBZ#1327786)