perf tools: Remove the '--(null)' long_name for --list-opts

If the long_name of a 'struct option' is defined as NULL, --list-opts
will incorrectly print '--(null)' in its output. As a result, '--(null)'
will finally appear in the case of bash completion, e.g. 'perf record
--'.

Example:

Before this patch:

 $ perf record --list-opts

 --event --filter --pid --tid --realtime --no-buffering --raw-samples
 --all-cpus --cpu --count --output --no-inherit --freq --mmap-pages
 --group --(null) --call-graph --verbose --quiet --stat --data
 --timestamp --period --no-samples --no-buildid-cache --no-buildid
 --cgroup --delay --uid --branch-any --branch-filter --weight
 --transaction --per-thread --intr-regs

After this patch:

 $ perf record --list-opts

 --event --filter --pid --tid --realtime --no-buffering --raw-samples
 --all-cpus --cpu --count --output --no-inherit --freq --mmap-pages
 --group --call-graph --verbose --quiet --stat --data --timestamp
 --period --no-samples --no-buildid-cache --no-buildid --cgroup --delay
 --uid --branch-any --branch-filter --weight --transaction --per-thread
 --intr-regs

Signed-off-by: Yunlong Song <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions