Clarify possible values for BDF_PropertyRec.
Minor documentation improvements.
[cff] Fix Savannah bug #41363.

* src/cff/cf2ft.c (cf2_checkTransform): Convert assertion into
parameter check.
(cf2_decoder_parse_charstrings): Call `cf2_checkTransform' only if
we are scaling the outline.
(cf2_getPpemY): Remove problematic assertion.
[autofit] Minor fix.

* src/autofit/afcjk.c (af_cjk_metrics_init_widths),
src/autofit/aflatin.c (af_latin_metrics_init_widths): Fix handling
of alternative standard characters.
This also fixes a compilation warning in non-debug mode.
Fix compilation with MinGW.

Right now, compilation out of the box with latest MinGW is broken
due to bugs in header files of mingwrt 4.0.3 in strict ANSI mode,
cf.

  https://sourceforge.net/p/mingw/bugs/2024/
  https://sourceforge.net/p/mingw/bugs/2046/

* builds/unix/configure.raw: Don't set `-ansi' flag for MinGW.
Work-around for Perl bug #63402.
Fix problems with perl 5.8.8 as distributed with current MinGW.

* src/tools/afblue.pl: Work-around for Perl bug #63402.
(string_re): Avoid `possessive quantifiers', which have been
introduced in Perl version 5.10.
Minor.