www/chromium: Unbreak build on < 11.3

In file included from gen/base/base_jumbo_17.cc:8:
./../../base/sampling_heap_profiler/sampling_heap_profiler.cc:74:3: error: use of undeclared identifier 'pthread_get_name_np'

pthread_get_name_np(pthread_self(), name, kBufferLen);
^

PR: 238563
Reported by: kib@