Add mac patch bzip2.

Will use Darwin linker args if we have a Darwin platform.

component/bzip2/Makefile-libbz2_so_mac.patch

+--- Makefile-libbz2_so	2012-05-19 16:17:59.000000000 +0200
++++ Makefile-libbz2_so2	2012-05-19 16:17:42.000000000 +0200
+@@ -34,8 +34,15 @@
+       decompress.o \
+       bzlib.o
+
++UNAME=$(shell uname)
++ifeq ($(UNAME), Darwin)
++  soname=-install_name
++else
++  soname=-soname
++endif
++
+ all: $(OBJS)
+-	$(CC) -shared -Wl,-soname -Wl,libbz2.so.1.0 -o libbz2.so.1.0.6 $(OBJS)
++	$(CC) -shared -Wl,$(soname) -Wl,libbz2.so.1.0 -o libbz2.so.1.0.6 $(OBJS)
+ 	$(CC) $(CFLAGS) -o bzip2-shared bzip2.c libbz2.so.1.0.6
+ 	rm -f libbz2.so.1.0
+ 	ln -s libbz2.so.1.0.6 libbz2.so.1.0

component/bzip2/buildout.cfg

@@ -9,10 +9,18 @@ md5sum = 066c8355b7d726f30176ea5b6a35e1a2
 download-only = true
 filename = bzip2-hooks.py
 
+[bzip2-Makefile-libbz2-so-mac.patch]
+recipe = hexagonit.recipe.download
+md5sum = be76b4f836977d32913087eeb4a74653
+url = ${:_profile_base_location_}/${:filename}
+filename = Makefile-libbz2_so_mac.patch
+download-only = true
+
 [bzip2]
 recipe = hexagonit.recipe.cmmi
 url = http://www.bzip.org/1.0.6/bzip2-1.0.6.tar.gz
 md5sum = 00b516f4704d4a7cb50a1d97e6e8e15b
+patches = ${bzip2-Makefile-libbz2-so-mac.patch:location}/${bzip2-Makefile-libbz2-so-mac.patch:filename}
 configure-command = true
 make-options =
   PREFIX=${buildout:parts-directory}/${:_buildout_section_name_}