Move pthread_*_np functions to correct BSD modules

These functions were never available on NetBSD, they belong to
OpenBSD/Bitrig.

src/unix/bsd/openbsdlike/bitrig.rs

@@ -227,6 +227,10 @@ extern {
                        flags: ::c_int) -> ::c_int;
     pub fn mprotect(addr: *const ::c_void, len: ::size_t, prot: ::c_int)
                     -> ::c_int;
+    pub fn pthread_main_np() -> ::c_int;
+    pub fn pthread_set_name_np(tid: ::pthread_t, name: *const ::c_char);
+    pub fn pthread_stackseg_np(thread: ::pthread_t,
+                               sinfo: *mut ::stack_t) -> ::c_int;
     pub fn sysctl(name: *mut ::c_int,
                   namelen: ::c_uint,
                   oldp: *mut ::c_void,

src/unix/bsd/openbsdlike/mod.rs

@@ -384,10 +384,6 @@ extern {
     pub fn __errno() -> *mut ::c_int;
     pub fn shm_open(name: *const ::c_char, oflag: ::c_int, mode: ::mode_t)
                     -> ::c_int;
-    pub fn pthread_main_np() -> ::c_int;
-    pub fn pthread_set_name_np(tid: ::pthread_t, name: *const ::c_char);
-    pub fn pthread_stackseg_np(thread: ::pthread_t,
-                               sinfo: *mut ::stack_t) -> ::c_int;
     pub fn memrchr(cx: *const ::c_void, c: ::c_int, n: ::size_t) -> *mut ::c_void;
     pub fn mkostemp(template: *mut ::c_char, flags: ::c_int) -> ::c_int;
     pub fn mkostemps(template: *mut ::c_char, suffixlen: ::c_int, flags: ::c_int) -> ::c_int;

src/unix/bsd/openbsdlike/openbsd.rs

@@ -232,6 +232,10 @@ extern {
                        flags: ::c_int) -> ::c_int;
     pub fn mprotect(addr: *mut ::c_void, len: ::size_t, prot: ::c_int)
                     -> ::c_int;
+    pub fn pthread_main_np() -> ::c_int;
+    pub fn pthread_set_name_np(tid: ::pthread_t, name: *const ::c_char);
+    pub fn pthread_stackseg_np(thread: ::pthread_t,
+                               sinfo: *mut ::stack_t) -> ::c_int;
     pub fn sysctl(name: *const ::c_int,
                   namelen: ::c_uint,
                   oldp: *mut ::c_void,