diff --git a/Makefile b/Makefile
index ab17fb7..92fda45 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 PREFIX = /usr/local
 LIBDIR = ${PREFIX}/lib
 INCLUDEDIR = ${PREFIX}/include
-XCFLAGS = ${CFLAGS} -std=c99 -fPIC -D_POSIX_VERSION=200809L -D_XOPEN_SOURCE=700 \
+XCFLAGS = ${CFLAGS} -std=c99 -fPIC -D_XOPEN_SOURCE=700 \
 		  -Wall -Wextra -Wpedantic -Wmissing-prototypes -Wstrict-prototypes -Wno-unused-parameter
 XLDFLAGS = ${LDFLAGS} -shared -Wl,-soname,libudev.so.1
 XARFLAGS = -rc