can't install ccxt on macos pycares issue

• OS: macOS 10.14.3 (18D109)
• Programming Language version: Python 3.7
• CCXT version: none, can’t install

i’m getting these errors about pycares during `pip install ccxt’

build/temp.macosx-10.14-x86_64-3.7/_cares.c:2573:55: error: too many arguments to function call, expected 6, have 7
      return ares_parse_ptr_reply(x0, x1, x2, x3, x4, x5, x6);
             ~~~~~~~~~~~~~~~~~~~~                         ^~
    /usr/local/include/ares.h:581:14: note: 'ares_parse_ptr_reply' declared here
    CARES_EXTERN int ares_parse_ptr_reply(const unsigned char *abuf,
build/temp.macosx-10.14-x86_64-3.7/_cares.c:4316:14: error: no member named 'ttl' in 'struct ares_mx_reply'
      (void)((p->ttl) | 0);  /* check that 'struct ares_mx_reply.ttl' is an integer */
              ~  ^
    build/temp.macosx-10.14-x86_64-3.7/_cares.c:4332:14: error: no member named 'ttl' in 'struct ares_naptr_reply'
      (void)((p->ttl) | 0);  /* check that 'struct ares_naptr_reply.ttl' is an integer */
              ~  ^
    build/temp.macosx-10.14-x86_64-3.7/_cares.c:4372:14: error: no member named 'ttl' in 'struct ares_soa_reply'
      (void)((p->ttl) | 0);  /* check that 'struct ares_soa_reply.ttl' is an integer */
              ~  ^
    build/temp.macosx-10.14-x86_64-3.7/_cares.c:4386:14: error: no member named 'ttl' in 'struct ares_srv_reply'
      (void)((p->ttl) | 0);  /* check that 'struct ares_srv_reply.ttl' is an integer */
              ~  ^
    build/temp.macosx-10.14-x86_64-3.7/_cares.c:4399:14: error: no member named 'ttl' in 'struct ares_txt_ext'
      (void)((p->ttl) | 0);  /* check that 'struct ares_txt_ext.ttl' is an integer */
              ~  ^
    build/temp.macosx-10.14-x86_64-3.7/_cares.c:4411:14: error: no member named 'ttl' in 'struct ares_txt_reply'
      (void)((p->ttl) | 0);  /* check that 'struct ares_txt_reply.ttl' is an integer */
              ~  ^
    build/temp.macosx-10.14-x86_64-3.7/_cares.c:4666:12: error: no member named 'ttl' in 'ares_mx_reply'
      { "ttl", offsetof(struct ares_mx_reply, ttl),
               ^                              ~~~
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/10.0.0/include/stddef.h:120:24: note: expanded from macro 'offsetof'
lots of errors with same output and then

 fatal error: too many errors emitted, stopping now [-ferror-limit=]
    20 errors generated.
    error: command 'clang' failed with exit status 1

[Queeq]

Found this solution: https://github.com/saghul/aiodns/issues/55#issuecomment-456330612

uninstall c-ares from /usr/local. pycares depends on the bundled version

Had to force uninstall as there are other dependables (e.g. Wireshark): brew uninstall --ignore-dependencies c-ares and it solved the issue. Wireshark still works though 😃

Also for the note (not sure if related), before removing c-ares, I did xcode-select --install according to the hint here: https://github.com/twintproject/twint/issues/101#issuecomment-390654795

[kroitor]

@Queeq thanks for the feedback, it will be very helpful to others!