Copy all stylesheet namespaces during apply-gen

* src/transform/apply-gen.xsl: Copy /xsl:*/namespace::*
* test/transform/apply-gen.xspec: Add respective test

src/transform/apply-gen.xsl

@@ -63,6 +63,10 @@
     </comment>
 
     <out:stylesheet version="2.0">
+      <!-- namespaces might be referenced in strings (e.g. @as), and so may
+           not be copied by default -->
+      <sequence select="namespace::*[ name() ]" />
+
       <xsl:apply-templates mode="fgen:create" />
     </out:stylesheet>
   </document>

test/transform/apply-gen.xspec

@@ -40,6 +40,21 @@
   </variable>
 
 
+  <!-- source namespaces must be copied -->
+  <scenario label="source namespaces">
+    <context>
+      <xsl:stylesheet xmlns:foobar="baz">
+        <xsl:function name="foobar:baz">
+          <xsl:param name="foo" />
+        </xsl:function>
+      </xsl:stylesheet>
+    </context>
+
+    <expect label="are copied to destination"
+            test="exists( xsl:stylesheet/namespace::foobar )" />
+  </scenario>
+
+
   <!-- basic case -->
   <scenario label="given a unary function">
     <context>