Ruby

• regenc.h/c: Rename onigenc_not_support_case_map to
  onigenc_ascii_only_case_map.
• regenc.h: Add definition of onigenc_single_byte_ascii_only_case_map.
• enc/iso_8859_X.c, windows_125X.c, ascii.c, us-ascii.c, koi8_x.c:
  Replace onigenc_not_support_case_map by
  onigenc_single_byte_ascii_only_case_map.
• enc/big5.c, cp949.c, emacs_mule.c, euc_X.c, gbX.c, shift_jis.c,
  windows_31j.c: Replace onigenc_not_support_case_map by
  onigenc_ascii_only_case_map.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55305 b2dd03c8-39d4-4d8f-98ff-823fe69b080e