With commit 4272a0b0fc curl-speficic
character classification macros and functions were introduced in
curl_ctype.[ch] to avoid dependencies on the locale. This broke curl on
non-ASCII, e.g. EBCDIC platforms. This change restores the previous set
of character classification macros when CURL_DOES_CONVERSIONS is
defined.
Closes#2494
On MinGW and Cygwin, GCC and clang have been complaining about macro
redefinitions since 4272a0b0fc. Fix this
by undefining the macros before redefining them as suggested in
https://github.com/curl/curl/pull/2269.
Suggested-by: Daniel Stenberg
... since the libc provided one are locale dependent in a way we don't
want. Also, the "native" isalnum() (for example) works differently on
different platforms which caused test 1307 failures on macos only.
Closes#2269
