Add comment noting the requirement to free replies when finished.

src/c-client.xsl

@@ -407,6 +407,8 @@ authorization from the authors.
         <doc> * The parameter @p e supplied to this function must be NULL if</doc>
         <doc> * <xsl:value-of select="xcb:xcb-prefix(@name)" />_unchecked(). is used.</doc>
         <doc> * Otherwise, it stores the error if any.</doc>
+        <doc> *</doc>
+        <doc> * The returned value must be freed by the caller using free().</doc>
         <doc> */</doc>
         <field type="xcb_connection_t *" name="c" />
         <field name="cookie">

xcb-xselinux.pc.in

+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: XCB SELinux
+Description: XCB SELinux Extension
+Version: @PACKAGE_VERSION@
+Requires: xcb
+Libs: -L${libdir} -lxcb-xselinux
+Cflags: -I${includedir}