fnetlock: fix unused bw variable warning

This is breaking build-clang on CI[1]:

    make -C src/fnetlock/
    make[1]: Entering directory '/home/runner/work/firejail/firejail/src/fnetlock'
    clang-14 [...] -c main.c -o main.o
    main.c:97:11: error: variable 'bw' set but not used [-Werror,-Wunused-but-set-variable]
            unsigned bw = 0; // bandwidth calculations
                     ^
    1 error generated.
    make[1]: *** [../../src/prog.mk:16: main.o] Error 1
    make: *** [Makefile:58: src/fnetlock/fnetlock] Error 2

Added on commit 8e4b847cd ("split nettrace executable ^Cto netrace and
netlock", 2023-07-25).

[1]: https://github.com/netblue30/firejail/actions/runs/5669072674/job/15361026508

Cc: @netblue30

1 files changed, 4 insertions, 2 deletions

diff --git a/src/fnetlock/main.c b/src/fnetlock/main.c
index b76be029d..d4169b7e1 100644
--- a/src/fnetlock/main.c
+++ b/src/fnetlock/main.c
@@ -94,7 +94,8 @@ static void run_trace(void) {
 
         unsigned start = time(NULL);
         unsigned char buf[MAX_BUF_SIZE];
-        unsigned bw = 0; // bandwidth calculations
+        // FIXME: error: variable 'bw' set but not used [-Werror,-Wunused-but-set-variable]
+        //unsigned bw = 0; // bandwidth calculations
 
         int printed = 0;
         while (1) {
@@ -149,7 +150,8 @@ static void run_trace(void) {
 #endif
                         // filter out loopback traffic
                         if (buf[12] != 127 && buf[16] != 127) {
-                                bw += bytes + 14; // assume a 14 byte Ethernet layer
+                                // FIXME: error: variable 'bw' set but not used [-Werror,-Wunused-but-set-variable]
+                                //bw += bytes + 14; // assume a 14 byte Ethernet layer
 
                                 uint32_t ip_src;
                                 memcpy(&ip_src, buf + 12, 4);