Add expectation for exit code propagation

Author: straight-shoota

spec/primitives/external_command_spec.cr

@@ -12,6 +12,8 @@ describe Crystal::Command do
           puts Process.find_executable("crystal")
           puts PROGRAM_NAME
           puts ARGV
+
+          exit 123
           CRYSTAL
 
         Process.run(compiler_path, ["build", source_file, "-o", command_path])
@@ -27,7 +29,8 @@ describe Crystal::Command do
       lines = process.output.gets_to_end.lines
 
       status = process.wait
-      status.success?.should be_true
+      status.normal_exit?.should be_true
+      status.exit_code.should eq 123
 
       lines.should eq [
         compiler_path,

src/compiler/crystal/command.cr

@@ -135,7 +135,7 @@ class Crystal::Command
         if executable_path = Process.executable_path
           crystal_path = File.dirname(executable_path)
         end
-        path = [crystal_path, ENV["PATH"]?].compact_map!.join(Process::PATH_DELIMITER)
+        path = [crystal_path, ENV["PATH"]?].compact!.join(Process::PATH_DELIMITER)
 
         Process.exec(external_command, options, env: {"PATH" => path})
       else