Add recipe for lxml

And patch, because they happily hardcode -lm in there...

dev-python/lxml/patches/python_lxml-3.3.5.patchset

@@ -0,0 +1,31 @@
+From 72985b29a3f51785c7fb070080861c815e6d3edd Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Fran=C3=A7ois=20Revol?= <revol@free.fr>
+Date: Tue, 29 Jul 2014 01:50:29 +0200
+Subject: [PATCH] Fix Haiku build (no libm)
+
+GRMBL !$*^= hardcoding
+---
+ setupinfo.py | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/setupinfo.py b/setupinfo.py
+index 4a1d150..4a5746d 100644
+--- a/setupinfo.py
++++ b/setupinfo.py
+@@ -186,9 +186,11 @@ def libraries():
+             libs = ['%s_a' % lib for lib in libs]
+         libs.extend(['zlib', 'WS2_32'])
+     elif OPTION_STATIC:
+-        libs = ['z', 'm']
++        libs = ['z']
+     else:
+-        libs = ['xslt', 'exslt', 'xml2', 'z', 'm']
++        libs = ['xslt', 'exslt', 'xml2', 'z']
++    if sys.platform[0:5] not in ('haiku','win32'):
++        libs.append('m')
+     return libs
+ 
+ def library_dirs(static_library_dirs):
+-- 
+1.8.3.4
+