Simple Example of Devenv Issue

.envrc

source_url "https://raw.githubusercontent.com/cachix/devenv/d1f7b48e35e6dee421cfd0f51481d17f77586997/direnvrc" "sha256-YBzqskFZxmNb3kYVoKD9ZixoPXJh1C9ZvTLGFRkauZ0="

use devenv

devenv.lock

{
  "nodes": {
    "devenv": {
      "locked": {
        "dir": "src/modules",
        "lastModified": 1687877315,
        "narHash": "sha256-PUzilA1dUdO+aQO1urBrjlmCbtEAJUmHg7k1P4o9tdE=",
        "owner": "cachix",
        "repo": "devenv",
        "rev": "36e0f2a9e3ba7b4e0cd77128c4b3551641dacd63",
        "type": "github"
      },
      "original": {
        "dir": "src/modules",
        "owner": "cachix",
        "repo": "devenv",
        "type": "github"
      }
    },
    "flake-compat": {
      "flake": false,
      "locked": {
        "lastModified": 1673956053,
        "narHash": "sha256-4gtG9iQuiKITOjNQQeQIpoIB6b16fm+504Ch3sNKLd8=",
        "owner": "edolstra",
        "repo": "flake-compat",
        "rev": "35bb57c0c8d8b62bbfd284272c928ceb64ddbde9",
        "type": "github"
      },
      "original": {
        "owner": "edolstra",
        "repo": "flake-compat",
        "type": "github"
      }
    },
    "flake-utils": {
      "inputs": {
        "systems": "systems"
      },
      "locked": {
        "lastModified": 1685518550,
        "narHash": "sha256-o2d0KcvaXzTrPRIo0kOLV0/QXHhDQ5DTi+OxcjO8xqY=",
        "owner": "numtide",
        "repo": "flake-utils",
        "rev": "a1720a10a6cfe8234c0e93907ffe81be440f4cef",
        "type": "github"
      },
      "original": {
        "owner": "numtide",
        "repo": "flake-utils",
        "type": "github"
      }
    },
    "gitignore": {
      "inputs": {
        "nixpkgs": [
          "pre-commit-hooks",
          "nixpkgs"
        ]
      },
      "locked": {
        "lastModified": 1660459072,
        "narHash": "sha256-8DFJjXG8zqoONA1vXtgeKXy68KdJL5UaXR8NtVMUbx8=",
        "owner": "hercules-ci",
        "repo": "gitignore.nix",
        "rev": "a20de23b925fd8264fd7fad6454652e142fd7f73",
        "type": "github"
      },
      "original": {
        "owner": "hercules-ci",
        "repo": "gitignore.nix",
        "type": "github"
      }
    },
    "nixpkgs": {
      "locked": {
        "lastModified": 1687793116,
        "narHash": "sha256-6xRgZ2E9r/BNam87vMkHJ/0EPTTKzeNwhw3abKilEE4=",
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "9e4e0807d2142d17f463b26a8b796b3fe20a3011",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
        "ref": "nixpkgs-unstable",
        "repo": "nixpkgs",
        "type": "github"
      }
    },
    "nixpkgs-stable": {
      "locked": {
        "lastModified": 1685801374,
        "narHash": "sha256-otaSUoFEMM+LjBI1XL/xGB5ao6IwnZOXc47qhIgJe8U=",
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "c37ca420157f4abc31e26f436c1145f8951ff373",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
        "ref": "nixos-23.05",
        "repo": "nixpkgs",
        "type": "github"
      }
    },
    "pre-commit-hooks": {
      "inputs": {
        "flake-compat": "flake-compat",
        "flake-utils": "flake-utils",
        "gitignore": "gitignore",
        "nixpkgs": [
          "nixpkgs"
        ],
        "nixpkgs-stable": "nixpkgs-stable"
      },
      "locked": {
        "lastModified": 1687779420,
        "narHash": "sha256-noueZE/Z5qx6NF/grg46qlpZ/1nuPpc92RvqgCmRaLI=",
        "owner": "cachix",
        "repo": "pre-commit-hooks.nix",
        "rev": "1fa438eee82f35bdd4bc30a9aacd7648d757b388",
        "type": "github"
      },
      "original": {
        "owner": "cachix",
        "repo": "pre-commit-hooks.nix",
        "type": "github"
      }
    },
    "root": {
      "inputs": {
        "devenv": "devenv",
        "nixpkgs": "nixpkgs",
        "pre-commit-hooks": "pre-commit-hooks"
      }
    },
    "systems": {
      "locked": {
        "lastModified": 1681028828,
        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
        "owner": "nix-systems",
        "repo": "default",
        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
        "type": "github"
      },
      "original": {
        "owner": "nix-systems",
        "repo": "default",
        "type": "github"
      }
    }
  },
  "root": "root",
  "version": 7
}

devenv.nix

{ pkgs, ... }:

{
  # https://devenv.sh/languages/
  languages.ruby.enable = true;
}

gem_make.out

current directory: /Users/tebriel/work/src/github.com/tebriel/devenv-em-bug/.devenv/state/.bundle/ruby/3.1.0/gems/eventmachine-1.2.7/ext
/nix/store/98wwdkbmqsygk1rpkfyd99dn9rcja34w-ruby-3.1.4/bin/ruby extconf.rb
checking for -lcrypto... no
checking for openssl/ssl.h... no
checking for rb_trap_immediate in ruby.h,rubysig.h... no
checking for rb_thread_blocking_region()... no
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for rb_thread_fd_select()... yes
checking for rb_fdset_t in ruby/intern.h... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_enable_interrupt()... no
checking for rb_time_new()... yes
checking for inotify_init() in sys/inotify.h... no
checking for __NR_inotify_init in sys/syscall.h... no
checking for writev() in sys/uio.h... yes
checking for pipe2() in unistd.h... no
checking for accept4() in sys/socket.h... no
checking for SOCK_CLOEXEC in sys/socket.h... no
checking for sys/event.h... yes
checking for sys/queue.h... yes
checking for clock_gettime()... yes
checking for CLOCK_MONOTONIC_RAW in time.h... yes
checking for CLOCK_MONOTONIC in time.h... yes
CXXFLAGS=-fdeclspec
creating Makefile

current directory: /Users/tebriel/work/src/github.com/tebriel/devenv-em-bug/.devenv/state/.bundle/ruby/3.1.0/gems/eventmachine-1.2.7/ext
make DESTDIR\= sitearchdir\=./.gem.20230627-45881-50zbq6 sitelibdir\=./.gem.20230627-45881-50zbq6 clean

current directory: /Users/tebriel/work/src/github.com/tebriel/devenv-em-bug/.devenv/state/.bundle/ruby/3.1.0/gems/eventmachine-1.2.7/ext
make DESTDIR\= sitearchdir\=./.gem.20230627-45881-50zbq6 sitelibdir\=./.gem.20230627-45881-50zbq6
compiling binder.cpp
compiling cmain.cpp
compiling ed.cpp
compiling em.cpp
compiling kb.cpp
compiling page.cpp
compiling pipe.cpp
compiling rubymain.cpp
rubymain.cpp:220:3: warning: 'rb_rescue' is deprecated: Use of ANYARGS in this function is deprecated [-Wdeprecated-declarations]
                rb_rescue((VALUE (*)(ANYARGS))event_callback, (VALUE)&e, (VALUE (*)(ANYARGS))event_error_handler, Qnil);
                ^
/nix/store/98wwdkbmqsygk1rpkfyd99dn9rcja34w-ruby-3.1.4/include/ruby-3.1.0/ruby/backward/cxxanyargs.hpp:246:1: note: 'rb_rescue' has been explicitly marked deprecated here
RUBY_CXX_DEPRECATED("Use of ANYARGS in this function is deprecated")
^
/nix/store/98wwdkbmqsygk1rpkfyd99dn9rcja34w-ruby-3.1.4/include/ruby-3.1.0/ruby/backward/2/attributes.h:78:35: note: expanded from macro 'RUBY_CXX_DEPRECATED'
#define RUBY_CXX_DEPRECATED(mseg) RBIMPL_ATTR_DEPRECATED((mseg))
                                  ^
/nix/store/98wwdkbmqsygk1rpkfyd99dn9rcja34w-ruby-3.1.4/include/ruby-3.1.0/ruby/internal/attr/deprecated.h:36:53: note: expanded from macro 'RBIMPL_ATTR_DEPRECATED'
# define RBIMPL_ATTR_DEPRECATED(msg) __attribute__((__deprecated__ msg))
                                                    ^
1 warning generated.
compiling ssl.cpp
linking shared-object rubyeventmachine.bundle
ld: warning: directory not found for option '-L/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-clang-wrapper-11.1.0/resource-root/lib'
ld: library not found for -lc++abi
clang-11: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:264: rubyeventmachine.bundle] Error 1

make failed, exit code 2

test.rb

require 'rbconfig'

puts RbConfig::MAKEFILE_CONFIG["LDFLAGS"]