+LDFLAGS += -lreadline
+LDFLAGS += -L/usr/X11/lib -lpng
+
+UNAME := $(shell uname)
+ifeq ($(UNAME),Darwin)
+CPPFLAGS += -DHAVE_FUNOPEN
+endif
+ifeq ($(UNAME),Linux)
+# linux needs _GNU_SOURCE for fopencookie
+# linux needs _XOPEN_SOURCE=600 (provided by _GNU_SOURCE) for getopt and strdup
+CPPFLAGS += -DHAVE_FOPENCOOKIE -D_GNU_SOURCE
+endif