How to resolve fatal error: 'openssl/ssl.h' file not found issue while install eventmachine gem 

when openssl3 and openssl1.1 both installed ,the path is '--with-cppflags=-I/usr/local/opt/openssl@1.1/include'

Run `brew --prefix openssl` to figure out where your openssl is installed and use the directory. Mine was installed in /opt/homebrew/opt/openssl because I reconfigured my homebrew to work with Mac M1.

Thank you! This helped me :)

I had the same problem when installing the Jekyll gem today. I found your video, added the flag at the end, and it worked! Thank you 😀 It might be worthwhile noting that everything from you solution after the gem name must be added: "-- --with-cppflags=-I/usr/local/opt/openssl/include". The first two dashes and the dash after the equal sign tripped me up the first time 😀

You might need to use the following path instead to install eventmachine (which i did): --with-cppflags=-I/usr/local/include/node

good job, helped me

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