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The CLONE_DETACHED thread is obsolete since 2.5 kernels.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/arch-x86/bionic/clone.S b/libc/arch-x86/bionic/clone.S
index e7bc3ee..80e3c75 100644
--- a/libc/arch-x86/bionic/clone.S
+++ b/libc/arch-x86/bionic/clone.S
@@ -1,7 +1,7 @@
 #include <machine/asm.h>
 #include <sys/linux-syscalls.h>
 
-// int  __pthread_clone(int (*fn)(void*), void* tls, int flags, void* arg);
+// int  __pthread_clone(void* (*fn)(void*), void* tls, int flags, void* arg);
 ENTRY(__pthread_clone)
         pushl   %ebx
         pushl   %ecx