maemo: Define _GNU_SOURCE to make llabs available.

llabs is defined in C99, thus requires e.g. _USE_ISOC99 to be defined.
features.h on Maemo defines _USE_ISOC99 in fewer cases than newer versions
of it do on other platforms.

packages/maemo-strongswan/debian/patches/llabs-needs-c99.patch

@@ -0,0 +1,13 @@
+llabs is defined in C99. features.h on other platforms enables C99 features
+automatically, here we explicitly enable them with _GNU_SOURCE (which enables
+also a lot of other things).
+--- a/src/libstrongswan/utils.c
++++ b/src/libstrongswan/utils.c
+@@ -14,6 +14,7 @@
+  * for more details.
+  */
+ 
++#define _GNU_SOURCE
+ #include "utils.h"
+ 
+ #include <sys/stat.h>

packages/maemo-strongswan/debian/patches/series

@@ -1,2 +1,3 @@
 shorter-timeout.patch
 configure-logging.patch
+llabs-needs-c99.patch