[gpsd-dev] [PATCH] fix building with clock_gettime and newer glibc

[Mike Frysinger]

Building with recent glibc versions fails in gpsutils.c due to missing
definitions related to clock_gettime.  This is because we define the
_XOPEN_SOURCE macro, but not to a new enough value.  So set it to a
recent spec value that satisfies both strptime and clock_gettime.

Example build failure with glibc-2.15:
gpsutils.c: In function 'timestamp':
gpsutils.c:299:22: error: storage size of 'ts' isn't known
gpsutils.c:300:14: warning: implicit declaration of function 'clock_gettime' 
[-Wimplicit-function-declaration]
gpsutils.c:300:34: error: 'CLOCK_REALTIME' undeclared (first use in this 
function)
gpsutils.c:300:34: note: each undeclared identifier is reported only once for 
each function it appears in

Signed-off-by: Mike Frysinger <address@hidden>
---
 gpsutils.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/gpsutils.c b/gpsutils.c
index 523838a..3b4990a 100644
--- a/gpsutils.c
+++ b/gpsutils.c
@@ -5,8 +5,10 @@
  */
 
 /* The strptime prototype is not provided unless explicitly requested.
- *  So add the define that POSIX says to to avoid: */
-#define _XOPEN_SOURCE
+ * We also need to set the value high enough to signal inclusion of
+ * newer features (like clock_gettime).  See the POSIX spec for more info:
+ * 
http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_02_01_02
 */
+#define _XOPEN_SOURCE 600
 
 #include <stdio.h>
 #include <time.h>
-- 
1.7.8.6