Fix the pthread_setname_np test.

Fix the pthread_setname_np test to take into account that emulator kernels are
so old that they don't support setting the name of other threads.

The CLONE_DETACHED thread is obsolete since 2.5 kernels.

Rename kernel_id to tid.

Fix the signature of __pthread_clone.

Clean up the clone and pthread_setname_np implementations slightly.

Change-Id: I16c2ff8845b67530544bbda9aa6618058603066d
diff --git a/libc/bionic/fork.c b/libc/bionic/fork.c
index 2d5a10a..d83c535 100644
--- a/libc/bionic/fork.c
+++ b/libc/bionic/fork.c
@@ -9,7 +9,7 @@
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the 
+ *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
@@ -19,7 +19,7 @@
  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
@@ -49,8 +49,8 @@
         __timer_table_start_stop(0);
         __bionic_atfork_run_parent();
     } else {
-        /* Adjusting the kernel id after a fork */
-        (void)__pthread_settid(pthread_self(), gettid());
+        // Fix the tid in the pthread_internal_t struct after a fork.
+        __pthread_settid(pthread_self(), gettid());
 
         /*
          * Newly created process must update cpu accounting.