diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
      CC = gcc -g -ggdb $(PROF)
     CPP = g++ -g -ggdb $(PROF)
  CFLAGS = -Wall -O2 -Iinclude $(EXTRA)
-  EXTRA = -D_XOPEN_SOURCE
+  EXTRA =
 LDFLAGS = -L/usr/lib
      RM = rm -f
    FIND = find