nptl: Remove lseek from libpthread

The libc version is identical and built with same flags.  The libc
version is set as the default version.

The libpthread compat symbol requires to mask it when building the
loader object otherwise ld might complain about a missing
versioned symbol (as for alpha).

Checked on x86_64-linux-gnu.

sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist

@@ -1860,6 +1860,7 @@ GLIBC_2.2 getwchar_unlocked F
 GLIBC_2.2 glob64 F
 GLIBC_2.2 iruserok_af F
 GLIBC_2.2 localeconv F
+GLIBC_2.2 lseek64 F
 GLIBC_2.2 mcheck_check_all F
 GLIBC_2.2 mcheck_pedantic F
 GLIBC_2.2 memrchr F

sysdeps/unix/sysv/linux/sparc/sparc32/libpthread.abilist

@@ -3,7 +3,6 @@ GLIBC_2.0 _IO_ftrylockfile F
 GLIBC_2.0 _IO_funlockfile F
 GLIBC_2.0 __errno_location F
 GLIBC_2.0 __h_errno_location F
-GLIBC_2.0 __lseek F
 GLIBC_2.0 __open F
 GLIBC_2.0 __pthread_getspecific F
 GLIBC_2.0 __pthread_key_create F
@@ -26,7 +25,6 @@ GLIBC_2.0 flockfile F
 GLIBC_2.0 ftrylockfile F
 GLIBC_2.0 funlockfile F
 GLIBC_2.0 longjmp F
-GLIBC_2.0 lseek F
 GLIBC_2.0 open F
 GLIBC_2.0 pthread_atfork F
 GLIBC_2.0 pthread_cancel F
@@ -122,7 +120,6 @@ GLIBC_2.2 __pthread_rwlock_unlock F
 GLIBC_2.2 __pthread_rwlock_wrlock F
 GLIBC_2.2 __pwrite64 F
 GLIBC_2.2 __res_state F
-GLIBC_2.2 lseek64 F
 GLIBC_2.2 open64 F
 GLIBC_2.2 pread F
 GLIBC_2.2 pread64 F

sysdeps/unix/sysv/linux/sparc/sparc64/libpthread.abilist

@@ -14,7 +14,6 @@ GLIBC_2.2 __h_errno_location F
 GLIBC_2.2 __libc_allocate_rtsig F
 GLIBC_2.2 __libc_current_sigrtmax F
 GLIBC_2.2 __libc_current_sigrtmin F
-GLIBC_2.2 __lseek F
 GLIBC_2.2 __open F
 GLIBC_2.2 __open64 F
 GLIBC_2.2 __pread64 F
@@ -48,8 +47,6 @@ GLIBC_2.2 flockfile F
 GLIBC_2.2 ftrylockfile F
 GLIBC_2.2 funlockfile F
 GLIBC_2.2 longjmp F
-GLIBC_2.2 lseek F
-GLIBC_2.2 lseek64 F
 GLIBC_2.2 open F
 GLIBC_2.2 open64 F
 GLIBC_2.2 pread F