core: fix build with toolchains not exporting CLOCK_BOOTTIME

E.G. uClibc 0.9.33 and earlier.

https://bugzilla.gnome.org/show_bug.cgi?id=734599

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Haller <thaller@redhat.com>

src/NetworkManagerUtils.c

@@ -44,6 +44,15 @@
 #include "nm-manager-auth.h"
 #include "nm-posix-signals.h"
 
+/*
+ * Some toolchains (E.G. uClibc 0.9.33 and earlier) don't export
+ * CLOCK_BOOTTIME even though the kernel supports it, so provide a
+ * local definition
+ */
+#ifndef CLOCK_BOOTTIME
+#define CLOCK_BOOTTIME 7
+#endif
+
 /*
  * nm_ethernet_address_is_valid
  *