getrandom syscall is not supported

This was introduced in musl 1.1.20.

Author: kleisauke

tools/system_libs.py

@@ -678,7 +678,7 @@ def get_files(self):
         'gethostbyname2_r.c', 'gethostbyname_r.c', 'gethostbyname2.c',
         'alarm.c', 'syscall.c', '_exit.c', 'popen.c',
         'getgrouplist.c', 'initgroups.c', 'wordexp.c', 'timer_create.c',
-        'faccessat.c', 'fopencookie.c', 'getentropy.c',
+        'faccessat.c', 'fopencookie.c', 'getentropy.c', 'getrandom.c',
         # 'process' exclusion
         'fork.c', 'vfork.c', 'posix_spawn.c', 'execve.c', 'waitid.c', 'system.c',
         'fexecve.c', '_Fork.c',