* configure.ac: Check for <sys/sendfile.h> and `sendfile'.
* libguile/filesys.c (scm_sendfile): New function.
* libguile/filesys.h (scm_sendfile): New declaration.
* test-suite/tests/filesys.test ("sendfile"): New test prefix.
* doc/ref/posix.texi (File System): Document `sendfile'.
* libguile/ports.h:
* libguile/ports.c (scm_consume_byte_order_mark): New procedure.
* libguile/fports.c (scm_open_file): Call consume-byte-order-mark if we
are opening a file in "r" mode.
* libguile/read.c (scm_i_scan_for_encoding): Don't do anything about
byte-order marks.
* libguile/load.c (scm_primitive_load): Add a note about the duplicate
encoding scan.
* test-suite/tests/filesys.test: Add tests for UTF-8, UTF-16BE, and
UTF-16LE BOM handling.