Fix assert_contains_make_command on make defined by environment varia…

…ble.

The `parse_make_command_line` in `assert_contains_make_command` fails to get
the make targets correctly, when the make command is set with make options by
environment variable such as `export make='make -j2'` at
lib/rubygems/ext/builder.rb::make.

So, we include the make options (eg, -XX) as a part of the command to fix the
case. Note that this commit still doesn't fix the case of
`export make='make -j 2'`.

test/rubygems/helper.rb

@@ -246,7 +246,7 @@ def scan_make_command_lines(output)
   end
 
   def parse_make_command_line(line)
-    command, *args = line.shellsplit
+    args = line.sub(/^#{Regexp.escape make_command}/, "").shellsplit
 
     targets = []
     macros = {}
@@ -263,7 +263,7 @@ def parse_make_command_line(line)
     targets << '' if targets.empty?
 
     {
-      :command => command,
+      :command => make_command,
       :targets => targets,
       :macros => macros,
     }

test/rubygems/test_gem_ext_ext_conf_builder.rb

@@ -66,8 +66,11 @@ def test_class_build_rbconfig_make_prog
     end
   end
 
-  def test_class_build_env_make
-    env_make = ENV.delete 'MAKE'
+  def test_class_build_env_MAKE
+    env_make = ENV.delete 'make'
+    ENV['make'] = nil
+
+    env_MAKE = ENV.delete 'MAKE'
     ENV['MAKE'] = 'anothermake'
 
     if java_platform?
@@ -89,7 +92,8 @@ def test_class_build_env_make
       assert_contains_make_command 'clean', output[4]
     end
   ensure
-    ENV['MAKE'] = env_make
+    ENV['MAKE'] = env_MAKE
+    ENV['make'] = env_make
   end
 
   def test_class_build_extconf_fail