workaround compile issues on Darwin (OS X)

Signed-off-by: Ben Noordhuis <info@bnoordhuis.nl>

Makefile

@@ -1,3 +1,4 @@
+UNAME := $(shell uname)
 NODE_PATH	=/usr/local
 
 LIBICONV_DIR	=deps/libiconv-1.13.1
@@ -6,7 +7,11 @@ LIBICONV	=$(LIBICONV_DIR)/lib/.libs/libiconv.a
 CXXFLAGS	=-I$(LIBICONV_DIR)/include -I$(NODE_PATH)/include/node -O2 -fPIC -Wall -ansi
 
 all:	$(LIBICONV) iconv.o
+ifeq ($(UNAME),Darwin)
+	$(CXX) -flat_namespace -undefined suppress -shared -o iconv.node iconv.o $(LIBICONV)
+else
 	$(CXX) -shared -o iconv.node iconv.o $(LIBICONV)
+endif
 
 install:	all
 	mkdir -p $(HOME)/.node_libraries && cp iconv.node $(HOME)/.node_libraries