I see the following error when compiling ruby from scratch using rbenv:

In file included from debug.c:27:
./vm_callinfo.h:183:9: error: use of undeclared identifier 'RUBY_FUNCTION_NAME_STRING'
        rp(ci);
        ^
./internal.h:89:72: note: expanded from macro 'rp'
#define rp(obj) rb_obj_info_dump_loc((VALUE)(obj), __FILE__, __LINE__, RUBY_FUNCTION_NAME_STRING)

I updated rbenv and rbenv-build to latest, to no avail.

According to stack overflow, the solution, that worked for me, was to update xcode:

The following worked for me:

You can use this pattern/idea:

CSV.new('string').method(:flock).source_location

Specifically for the wco  stack, gem 'iron_warbler' had to be included in that particular instance's (micros_*) Gemfile. Which is a bit disappointing since I wanted libraries to be decoupled - but hey, I'm not going to fix this right now. But please be aware: it may seem that there is a separation between libraries and some libraries (namely models and content) can be installed without the rest of the stack - but that's not the case. The whole stack must be installed.

Change

host: localhost

to 

host: 127.0.0.1

in config/database.yml, to make the connection over TCP/IP rather than local socket.

This questions is answered on Stack Overflow. 

This happens on older versions of ruby and rails.

Solved by downgrading psych:

# Gemfile
gem 'psych', '< 4'

You can do the following in your Gemfile, but then you'd have to switch the Gemfile between development and production, which is not recommended:

# Gemfile 
gem "foo", path: "/path/to/foo" 

Alternatively, you can tell Bundler to use a local gem in your current environment. This is preferred as the Gemfile still points to the production version of the gem. Run this in shell:

 bundle config set local.GEM_NAME /path/to/local/git/repository

Ruby on Rails, a menudo llamado simplemente Rails, es un marco de aplicación web escrito en Ruby. Fue creado por David Heinemeier Hansson y lanzado en 2004. Rails está diseñado para facilitar la programación de aplicaciones web al hacer suposiciones sobre lo que cada desarrollador necesita para comenzar. Permite a los desarrolladores escribir menos código y lograr más que muchos otros lenguajes y marcos.