move help text from include/usage.src.h to coreutils/*.c

Signed-off-by: Pere Orga <gotrunks@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/sync.c b/coreutils/sync.c
index bb112ea..7d98a1e 100644
--- a/coreutils/sync.c
+++ b/coreutils/sync.c
@@ -9,6 +9,11 @@
 
 /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
 
+//usage:#define sync_trivial_usage
+//usage:       ""
+//usage:#define sync_full_usage "\n\n"
+//usage:       "Write all buffered blocks to disk"
+
 #include "libbb.h"
 
 /* This is a NOFORK applet. Be very careful! */