I've been trying to install msgpack using homebrew, and it repeatedly throw the following error:
Building native extensions. This could take a while...
ERROR: Error installing msgpack:
ERROR: Failed to build gem native extension.
current directory: /usr/local/lib/ruby/gems/2.4.0/gems/msgpack
0.5.8/ext/msgpack
/usr/local/opt/ruby/bin/ruby -r ./siteconf20170801-23901-1ar0ojr.rb extconf.rb
checking for ruby/st.h... yes
checking for st.h... yes
checking for rb_str_replace() in ruby.h... yes
creating Makefile
current directory: /usr/local/lib/ruby/gems/2.4.0/gems/msgpack-
0.5.8/ext/msgpack
make "DESTDIR=" clean
current directory: /usr/local/lib/ruby/gems/2.4.0/gems/msgpack-
0.5.8/ext/msgpack
make "DESTDIR="
compiling buffer.c
compiling buffer_class.c
compiling core_ext.c
core_ext.c:121:22: error: use of undeclared identifier 'rb_cFixnum'
rb_define_method(rb_cFixnum, "to_msgpack", Fixnum_to_msgpack, -1);
^
core_ext.c:122:22: error: use of undeclared identifier 'rb_cBignum'
rb_define_method(rb_cBignum, "to_msgpack", Bignum_to_msgpack, -1);
^
2 errors generated.
make: *** [core_ext.o] Error 1
make failed, exit code 2
Gem files will remain installed in
/usr/local/lib/ruby/gems/2.4.0/gems/msgpack-0.5.8 for inspection.
Results logged to /usr/local/lib/ruby/gems/2.4.0/extensions/x86_64-darwin-
16/2.4.0/msgpack-0.5.8/gem_make.out
Searching for the solution to this has been unfruitful. My Ruby version is 2.4.1, but I'm not sure if it's a version issue.