Fixes <http://bugs.gnu.org/16463>.
Reported by Sree Harsha Totakura <sreeharsha@totakura.in>.
* libguile/read.c (ENCODING_NAME_MAX_SIZE): New macro.
(SCM_ENCODING_SEARCH_SIZE): Change to 500 + ENCODING_NAME_MAX_SIZE.
(scm_i_scan_for_encoding): Return NULL if there's less than
ENCODING_NAME_MAX_SIZE bytes once "coding: *" has been read.
* test-suite/tests/coding.test ("line
comment")["http://bugs.gnu.org/16463"]: New test.
* libguile/fports.c (scm_open_file): Do not scan for coding
declarations. Replace 'use_encoding' local variable with
'binary'. Update documentation string.
* module/ice-9/psyntax.scm (include): Add the same file-encoding
logic that's used in compile-file and scm_primitive_load.
* module/ice-9/psyntax-pp.scm: Regenerate.
* doc/ref/api-io.texi (File Ports): Update docs.
* test-suite/tests/ports.test: Change "open-file HONORS file coding
declarations" test to "open-file IGNORES file coding declaration".
* test-suite/tests/coding.test (scan-coding): Use 'file-encoding' to
scan for the encoding, since 'open-input-file' no longer does so.
* libguile/read.c (scm_i_scan_for_encoding): Fix for coding on first
line #! and for !# immediately following the coding.
* test-suite/Makefile.am:
* test-suite/tests/coding.test: Add tests.
