gistfile1.txt

 gem i json        
Fetching: json-1.8.1.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing json:
        ERROR: Failed to build gem native extension.

    /Users/miyagawa/.rbenv/versions/2.2.0/bin/ruby -r ./siteconf20141225-12006-1tf9ofy.rb extconf.rb
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling generator.c
In file included from generator.c:1:
./../fbuffer/fbuffer.h:175:47: error: too few arguments provided to function-like macro invocation
    VALUE result = rb_str_new(FBUFFER_PAIR(fb));
                                              ^
/Users/miyagawa/.rbenv/versions/2.2.0/include/ruby-2.2.0/ruby/intern.h:793:9: note: macro 'rb_str_new' defined here
#define rb_str_new(str, len) __extension__ (    \
        ^
In file included from generator.c:1:
./../fbuffer/fbuffer.h:175:11: warning: incompatible pointer to integer conversion initializing 'VALUE' (aka 'unsigned long') with an expression of type 'VALUE (const char *, long)' [-Wint-conversion]
    VALUE result = rb_str_new(FBUFFER_PAIR(fb));
          ^        ~~~~~~~~~~
1 warning and 1 error generated.
make: *** [generator.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/miyagawa/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/gems/json-1.8.1 for inspection.
Results logged to /Users/miyagawa/.rbenv/versions/2.2.0/lib/ruby/gems/2.2.0/extensions/x86_64-darwin-13/2.2.0-static/json-1.8.1/gem_make.out