Split libX11-xcb to its own subpackage. This doesn't have much effect at

the moment because x11-xcb.pc still lists both libX11 and libxcb in
  Requires, but once that's fixed eg. libEGL should be able to be installed
  without libX11.

libX11.spec

@@ -5,7 +5,7 @@
 Summary: Core X11 protocol client library
 Name: libX11
 Version: 1.6.5
-Release: 3%{?gitdate:.%{gitdate}git%{gitversion}}%{?dist}
+Release: 4%{?gitdate:.%{gitdate}git%{gitversion}}%{?dist}
 License: MIT
 Group: System Environment/Libraries
 URL: http://www.x.org
@@ -44,10 +44,19 @@ libX11 common data
 Summary: Development files for %{name}
 Group: Development/Libraries
 Requires: %{name} = %{version}-%{release}
+Requires: %{name}-xcb = %{version}-%{release}
 
 %description devel
 X.Org X11 libX11 development package
 
+%package xcb
+Summary: XCB interop for libX11
+Group: System Environment/Libraries
+Conflicts: %{name} < %{version}-%{release}
+
+%description xcb
+libX11/libxcb interoperability library
+
 %prep
 %setup -q -n %{tarball}-%{?gitdate:%{gitdate}}%{!?gitdate:%{version}}
 %patch2 -p1 -b .dont-forward-keycode-0
@@ -79,6 +88,8 @@ rm -rf $RPM_BUILD_ROOT%{_docdir}
 %files
 %{_libdir}/libX11.so.6
 %{_libdir}/libX11.so.6.3.0
+
+%files xcb
 %{_libdir}/libX11-xcb.so.1
 %{_libdir}/libX11-xcb.so.1.0.0
 
@@ -110,6 +121,12 @@ rm -rf $RPM_BUILD_ROOT%{_docdir}
 %{_mandir}/man5/*.5*
 
 %changelog
+* Tue Aug 01 2017 Adam Jackson <ajax@redhat.com> - 1.6.5-4
+- Split libX11-xcb to its own subpackage. This doesn't have much effect at
+  the moment because x11-xcb.pc still lists both libX11 and libxcb in
+  Requires, but once that's fixed eg. libEGL should be able to be installed
+  without libX11.
+
 * Wed Jul 26 2017 Fedora Release Engineering <releng@fedoraproject.org> - 1.6.5-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_27_Mass_Rebuild