The template swap() implementation does not compile with gcc-4.9.4,
but fortunately it is not yet used anywhere in the code, thus just
rip it out.

--- src/lib/util/vecstream.h	2016-08-31 03:47:01.000000000 +0200
+++ src/lib/util/vecstream.h	2016-08-31 08:46:11.374477157 +0200
@@ -107,15 +107,6 @@
 		setup();
 	}
 
-	void swap(basic_vectorbuf &that)
-	{
-		using std::swap;
-		std::basic_streambuf<CharT, Traits>::swap(that);
-		swap(m_mode, that.m_mode);
-		swap(m_storage, that.m_storage);
-		swap(m_threshold, that.m_threshold);
-	}
-
 	void reserve(typename vector_type::size_type size)
 	{
 		if ((m_mode & std::ios_base::out) && (m_storage.capacity() < size))
@@ -327,8 +318,6 @@
 	void vec(const vector_type &content) { rdbuf()->vec(content); }
 	void vec(vector_type &&content) { rdbuf()->vec(std::move(content)); }
 
-	void swap(basic_ivectorstream &that) { std::basic_istream<CharT, Traits>::swap(that); rdbuf()->swap(*that.rdbuf()); }
-
 private:
 	basic_vectorbuf<CharT, Traits, Allocator> m_rdbuf;
 };
@@ -350,8 +339,6 @@
 	void vec(vector_type &&content) { rdbuf()->vec(std::move(content)); }
 	basic_ovectorstream &reserve(typename vector_type::size_type size) { rdbuf()->reserve(size); return *this; }
 
-	void swap(basic_ovectorstream &that) { std::basic_ostream<CharT, Traits>::swap(that); rdbuf()->swap(*that.rdbuf()); }
-
 private:
 	basic_vectorbuf<CharT, Traits, Allocator> m_rdbuf;
 };
@@ -373,8 +360,6 @@
 	void vec(vector_type &&content) { rdbuf()->vec(std::move(content)); }
 	basic_vectorstream &reserve(typename vector_type::size_type size) { rdbuf()->reserve(size); return *this; }
 
-	void swap(basic_vectorstream &that) { std::basic_iostream<CharT, Traits>::swap(that); rdbuf()->swap(*that.rdbuf()); }
-
 private:
 	basic_vectorbuf<CharT, Traits, Allocator> m_rdbuf;
 };
@@ -386,16 +371,6 @@
 typedef basic_vectorstream<char>        vectorstream;
 typedef basic_vectorstream<wchar_t>     wvectorstream;
 
-template <typename CharT, typename Traits, typename Allocator>
-void swap(basic_vectorbuf<CharT, Traits, Allocator> &a, basic_vectorbuf<CharT, Traits, Allocator> &b) { a.swap(b); }
-
-template <typename CharT, typename Traits, typename Allocator>
-void swap(basic_ivectorstream<CharT, Traits, Allocator> &a, basic_ivectorstream<CharT, Traits, Allocator> &b) { a.swap(b); }
-template <typename CharT, typename Traits, typename Allocator>
-void swap(basic_ovectorstream<CharT, Traits, Allocator> &a, basic_ovectorstream<CharT, Traits, Allocator> &b) { a.swap(b); }
-template <typename CharT, typename Traits, typename Allocator>
-void swap(basic_vectorstream<CharT, Traits, Allocator> &a, basic_vectorstream<CharT, Traits, Allocator> &b) { a.swap(b); }
-
 extern template class basic_ivectorstream<char>;
 extern template class basic_ivectorstream<wchar_t>;
 extern template class basic_ovectorstream<char>;