'stdlib.h' file not found

[domoritz]

I'm trying to install jekyll and it fails with 'stdlib.h' file not found. Do you have suggestions for how to resolve this?

Installing commonmarker 0.17.9 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /usr/local/lib/ruby/gems/2.5.0/gems/commonmarker-0.17.9/ext/commonmarker
/usr/local/opt/ruby/bin/ruby -r ./siteconf20181027-45141-1azopun.rb extconf.rb
creating Makefile

current directory: /usr/local/lib/ruby/gems/2.5.0/gems/commonmarker-0.17.9/ext/commonmarker
make "DESTDIR=" clean

current directory: /usr/local/lib/ruby/gems/2.5.0/gems/commonmarker-0.17.9/ext/commonmarker
make "DESTDIR="
compiling arena.c
arena.c:1:10: fatal error: 'stdlib.h' file not found
#include <stdlib.h>
         ^~~~~~~~~~
1 error generated.
make: *** [arena.o] Error 1

make failed, exit code 2

Gem files will remain installed in /usr/local/lib/ruby/gems/2.5.0/gems/commonmarker-0.17.9 for inspection.
Results logged to /usr/local/lib/ruby/gems/2.5.0/extensions/x86_64-darwin-18/2.5.0/commonmarker-0.17.9/gem_make.out

An error occurred while installing commonmarker (0.17.9), and Bundler cannot continue.
Make sure that `gem install commonmarker -v '0.17.9' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile:
  github-pages was resolved to 188, which depends on
    jekyll-commonmark-ghpages was resolved to 0.1.5, which depends on
      jekyll-commonmark was resolved to 1.2.0, which depends on
        commonmarker

[domoritz]

I had to run sudo ln -sf /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include /usr/include to fix it.

[ppamorim]

@domoritz Do not run this script on macOS Catalina. If you did, run this:

find usr/local/include -lname '/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/*' -delete

[bobtista]

find usr/local/include -lname '/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/*' -delete

My hero! Fixed an issue where VSCode debugger wouldn't run. Note I had to run this from root directory, but it worked. Thank you!