make the package build on Fedora 28

FIXME: The resulting binaries cannot work properly!!!

libnice.spec

@@ -77,6 +77,13 @@ autoreconf -fiv
 
 
 %build
+export CFLAGS="$RPM_OPT_FLAGS"
+%if 0%{?fedora} == 28
+# FIXME: This makes the code compile on Fedora 28 but the resulting binaries
+# cannot work properly!!!
+CFLAGS="$CFLAGS -Wno-error=cast-function-type"
+%endif
+
 %configure --disable-static \
 %if %{with gst010}
  --with-gstreamer-0.10
@@ -128,6 +135,7 @@ find $RPM_BUILD_ROOT -name '*.la' -exec rm -f {} ';'
 
 %changelog
 * Fri Feb 09 2018 Kamil Dudka <kdudka@redhat.com> - 0.1.14-4.20171128gitfb2f1f7
+- make the package build on Fedora 28
 - avoid build failure if gstreamer-plugins-base-devel is installed
 - move autoreconf invocation to %%prep
 - use Name Version Release that explicitly identifies an SCM snapshot (#1541646)