From 671e2bb5b5fa00bd8094ce8c1ee61b8a607604ee Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Wed, 12 Apr 2017 22:11:09 -0700
Subject: [PATCH] Compile programs with -D_POSIX_C_SOURCE=200809L

The _DEFAULT_SOURCE feature test macro is only supported by glibc 2.19
and later.  As a result, various things were not being defined when
building with an older glibc version, causing compile errors.  Instead,
_POSIX_C_SOURCE=200809L should expose everything we need.
---
 Makefile | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index a9d9129..ce8c530 100644
--- a/Makefile
+++ b/Makefile
@@ -141,9 +141,9 @@ DEFAULT_TARGETS += $(SHARED_LIB)
 
 #### Programs
 
-PROG_CFLAGS += $(CFLAGS)		\
-	       -D_DEFAULT_SOURCE	\
-	       -D_FILE_OFFSET_BITS=64	\
+PROG_CFLAGS += $(CFLAGS)		 \
+	       -D_POSIX_C_SOURCE=200809L \
+	       -D_FILE_OFFSET_BITS=64	 \
 	       -DHAVE_CONFIG_H
 
 PROG_COMMON_HEADERS := programs/prog_util.h programs/config.h