1 files changed, 1 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 09b21541e..6d37d55b4 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@ INSTALL = install
 DIFF    = diff
 PREFIX  ?= /usr/local
 MANDIR  ?= $(PREFIX)/share/man
-CFLAGS  ?= -Os -Wall -Wextra -Wno-unused-parameter -Wshadow -Wmissing-prototypes -Wwrite-strings
+CFLAGS  ?= -std=c99 -D_DEFAULT_SOURCE -D_POSIX_C_SOURCE=200809L -D_BSD_SOURCE -Os -Wall -Wextra -Wno-unused-parameter -Wshadow -Wmissing-prototypes -Wwrite-strings
 EXPORTDIR ?= .
 RANLIB  ?= ranlib
 PKG_CONFIG ?= pkg-config