* ptexenc.c: Return replacement character U+FFFD
for illegal surrogate pair in console (keyboard) input
in upTeX on Windows.
* ptexenc.c, ptexenc/unicode.h: Enable console (keyboard) input
of Unicode characters in upTeX on Windows.
* configure.ac (AH_TOP): Simplify the generation of c-auto.h.
* ptexenc.c: Provide right console output on windows for both
ptex and uptex if --sjis-terminal option is given. (from T. Tanaka).
* ptexenc.c: Remove redundant lines in input_line2(), which are
inconsistent with those lines in texmfmp.c.
ptexenc is a useful library for Japanese pTeX (which stands for
publishing TeX, and is an extension of TeX by ASCII Co.) and its
surrounding tools. ptexenc provides a better way of handling
character encodings.