diff --git a/Makefile b/Makefile
index 34acd79..17e20e2 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,8 @@ CC = clang
 CFLAGS = -std=c99 -Wall -Wextra -Wno-unused-function \
 	-ggdb -fsanitize=address,undefined
 # -lpthread is only there for debugging (gdb & errno)
-LDFLAGS = `pkg-config --libs libssl` -lpthread
+# -lrt is only for glibc < 2.17
+LDFLAGS = `pkg-config --libs libssl` -lpthread -lrt
 
 .PHONY: all clean
 .SUFFIXES: