Move usage text into usage_str var

For consistency and readability.

Note: This also makes exactly one extra blank line be printed at the end
of every usage text, which is currently only done in the following
files:

* src/fcopy/main.c
* src/fnettrace-dns/main.c
* src/fnettrace-icmp/main.c
* src/fnettrace-sni/main.c
* src/fnettrace/main.c
* src/profstats/main.c

1 files changed, 4 insertions, 1 deletions

diff --git a/src/ftee/main.c b/src/ftee/main.c
index 0a492b41e..a34a76b26 100644
--- a/src/ftee/main.c
+++ b/src/ftee/main.c
@@ -180,8 +180,11 @@ static int is_link(const char *fname) {
         return 0;
 }
 
+static const char *const usage_str =
+        "Usage: ftee filename\n";
+
 static void usage(void) {
-        printf("Usage: ftee filename\n");
+        puts(usage_str);
 }
 
 int main(int argc, char **argv) {