configure: Make NPTL non-optional

Now all linux-user targets support building with NPTL, we can make it
mandatory. This is a good idea because:
 * NPTL is no longer new and experimental; it is completely standard
 * in practice, linux-user without NPTL is nearly useless for
   binaries built against non-ancient glibc
 * it allows us to delete the rather untested code for handling
   the non-NPTL configuration

Note that this patch leaves the CONFIG_USE_NPTL ifdefs in the
bsd-user codebase alone. This makes no change for bsd-user, since
our configure test for NPTL had a "#include <linux/futex.h>"
which means bsd-user would never have been compiled with
CONFIG_USE_NPTL defined, and it still is not.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d3b3590..5bd57d0 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -111,13 +111,8 @@
 
 #include "qemu.h"
 
-#if defined(CONFIG_USE_NPTL)
 #define CLONE_NPTL_FLAGS2 (CLONE_SETTLS | \
     CLONE_PARENT_SETTID | CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)
-#else
-/* XXX: Hardcode the above values.  */
-#define CLONE_NPTL_FLAGS2 0
-#endif
 
 //#define DEBUG
 
@@ -234,12 +229,10 @@
 #if defined(TARGET_NR_set_tid_address) && defined(__NR_set_tid_address)
 _syscall1(int,set_tid_address,int *,tidptr)
 #endif
-#if defined(CONFIG_USE_NPTL)
 #if defined(TARGET_NR_futex) && defined(__NR_futex)
 _syscall6(int,sys_futex,int *,uaddr,int,op,int,val,
           const struct timespec *,timeout,int *,uaddr2,int,val3)
 #endif
-#endif
 #define __NR_sys_sched_getaffinity __NR_sched_getaffinity
 _syscall3(int, sys_sched_getaffinity, pid_t, pid, unsigned int, len,
           unsigned long *, user_mask_ptr);
@@ -4227,7 +4220,6 @@
 
 #define NEW_STACK_SIZE 0x40000
 
-#if defined(CONFIG_USE_NPTL)
 
 static pthread_mutex_t clone_lock = PTHREAD_MUTEX_INITIALIZER;
 typedef struct {
@@ -4272,16 +4264,6 @@
     /* never exits */
     return NULL;
 }
-#else
-
-static int clone_func(void *arg)
-{
-    CPUArchState *env = arg;
-    cpu_loop(env);
-    /* never exits */
-    return 0;
-}
-#endif
 
 /* do_fork() Must return host values and target errnos (unlike most
    do_*() functions). */
@@ -4292,12 +4274,8 @@
     int ret;
     TaskState *ts;
     CPUArchState *new_env;
-#if defined(CONFIG_USE_NPTL)
     unsigned int nptl_flags;
     sigset_t sigmask;
-#else
-    uint8_t *new_stack;
-#endif
 
     /* Emulate vfork() with fork() */
     if (flags & CLONE_VFORK)
@@ -4305,10 +4283,9 @@
 
     if (flags & CLONE_VM) {
         TaskState *parent_ts = (TaskState *)env->opaque;
-#if defined(CONFIG_USE_NPTL)
         new_thread_info info;
         pthread_attr_t attr;
-#endif
+
         ts = g_malloc0(sizeof(TaskState));
         init_task_state(ts);
         /* we create a new CPU instance. */
@@ -4321,7 +4298,6 @@
         new_env->opaque = ts;
         ts->bprm = parent_ts->bprm;
         ts->info = parent_ts->info;
-#if defined(CONFIG_USE_NPTL)
         nptl_flags = flags;
         flags &= ~CLONE_NPTL_FLAGS2;
 
@@ -4371,17 +4347,6 @@
         pthread_cond_destroy(&info.cond);
         pthread_mutex_destroy(&info.mutex);
         pthread_mutex_unlock(&clone_lock);
-#else
-        if (flags & CLONE_NPTL_FLAGS2)
-            return -EINVAL;
-        /* This is probably going to die very quickly, but do it anyway.  */
-        new_stack = g_malloc0 (NEW_STACK_SIZE);
-#ifdef __ia64__
-        ret = __clone2(clone_func, new_stack, NEW_STACK_SIZE, flags, new_env);
-#else
-	ret = clone(clone_func, new_stack + NEW_STACK_SIZE, flags, new_env);
-#endif
-#endif
     } else {
         /* if no CLONE_VM, we consider it is a fork */
         if ((flags & ~(CSIGNAL | CLONE_NPTL_FLAGS2)) != 0)
@@ -4392,7 +4357,6 @@
             /* Child Process.  */
             cpu_clone_regs(env, newsp);
             fork_end(1);
-#if defined(CONFIG_USE_NPTL)
             /* There is a race condition here.  The parent process could
                theoretically read the TID in the child process before the child
                tid is set.  This would require using either ptrace
@@ -4408,7 +4372,6 @@
                 cpu_set_tls (env, newtls);
             if (flags & CLONE_CHILD_CLEARTID)
                 ts->child_tidptr = child_tidptr;
-#endif
         } else {
             fork_end(0);
         }
@@ -4834,7 +4797,6 @@
 }
 #endif
 
-#if defined(CONFIG_USE_NPTL)
 /* ??? Using host futex calls even when target atomic operations
    are not really atomic probably breaks things.  However implementing
    futexes locally would make futexes shared between multiple processes
@@ -4886,7 +4848,6 @@
         return -TARGET_ENOSYS;
     }
 }
-#endif
 
 /* Map host to target signal numbers for the wait family of syscalls.
    Assume all other status bits are the same.  */
@@ -5132,9 +5093,7 @@
                     abi_long arg5, abi_long arg6, abi_long arg7,
                     abi_long arg8)
 {
-#ifdef CONFIG_USE_NPTL
     CPUState *cpu = ENV_GET_CPU(cpu_env);
-#endif
     abi_long ret;
     struct stat st;
     struct statfs stfs;
@@ -5148,7 +5107,6 @@
 
     switch(num) {
     case TARGET_NR_exit:
-#ifdef CONFIG_USE_NPTL
         /* In old applications this may be used to implement _exit(2).
            However in threaded applictions it is used for thread termination,
            and _exit_group is used for application termination.
@@ -5186,7 +5144,6 @@
             g_free(ts);
             pthread_exit(NULL);
         }
-#endif
 #ifdef TARGET_GPROF
         _mcleanup();
 #endif
@@ -8687,11 +8644,9 @@
         }
 	break;
 #endif
-#if defined(CONFIG_USE_NPTL)
     case TARGET_NR_futex:
         ret = do_futex(arg1, arg2, arg3, arg4, arg5, arg6);
         break;
-#endif
 #if defined(TARGET_NR_inotify_init) && defined(__NR_inotify_init)
     case TARGET_NR_inotify_init:
         ret = get_errno(sys_inotify_init());