Relocate alpha from ports to libc

Also fixed the following whitespace nits to satisfy the push:

sysdeps/alpha/alphaev6/memset.S:142: space before tab in indent.
sysdeps/alpha/configure:1: new blank line at EOF.
sysdeps/alpha/fpu/e_sqrt.c:126: space before tab in indent.
sysdeps/alpha/preconfigure:1: new blank line at EOF.
sysdeps/unix/sysv/linux/alpha/syscalls.list:1: new blank line at EOF.

sysdeps/unix/sysv/linux/alpha/bits/errno.h

@@ -0,0 +1,65 @@
+/* Error constants.  Linux/Alpha specific version.
+   Copyright (C) 1996-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifdef _ERRNO_H
+
+# undef EDOM
+# undef EILSEQ
+# undef ERANGE
+# include <linux/errno.h>
+
+/* Linux has no ENOTSUP error code.  */
+# define ENOTSUP EOPNOTSUPP
+
+# ifndef ECANCELED
+#  define ECANCELED	131
+# endif
+
+/* Support for error codes to support robust mutexes was added later, too.  */
+# ifndef EOWNERDEAD
+#  define EOWNERDEAD		136
+#  define ENOTRECOVERABLE	137
+# endif
+
+# ifndef ERFKILL
+#  define ERFKILL		138
+# endif
+
+# ifndef EHWPOISON
+#  define EHWPOISON		139
+# endif
+
+# ifndef __ASSEMBLER__
+/* Function to get address of global `errno' variable.  */
+extern int *__errno_location (void) __THROW __attribute__ ((__const__));
+
+#  if !defined _LIBC || defined _LIBC_REENTRANT
+/* When using threads, errno is a per-thread value.  */
+#   define errno (*__errno_location ())
+#  endif
+# endif /* !__ASSEMBLER__ */
+#endif /* _ERRNO_H */
+
+#if !defined _ERRNO_H && defined __need_Emath
+/* This is ugly but the kernel header is not clean enough.  We must
+   define only the values EDOM, EILSEQ and ERANGE in case __need_Emath is
+   defined.  */
+# define EDOM	33	/* Math argument out of domain of function.  */
+# define EILSEQ	116	/* Illegal byte sequence.  */
+# define ERANGE	34	/* Math result not representable.  */
+#endif /* !_ERRNO_H && __need_Emath */