README: mention that the Prevention DS-2200PV uses the same protocol

[visomat-utils.git] / src / Makefile

diff --git a/src/Makefile b/src/Makefile
index 4ac4019..79105ea 100644 (file)
--- a/src/Makefile
+++ b/src/Makefile
@@ -36,6 +36,9 @@ ifeq ($(DEBUG),1)
   CFLAGS += -DDEBUG
 endif
 
+# for getopt
+CFLAGS += -D_POSIX_C_SOURCE=2
+
 CFLAGS += $(shell pkg-config --cflags libusb-1.0)
 LDLIBS := $(shell pkg-config --libs libusb-1.0)