extmk.rb: discard empty Makefile

* ext/extmk.rb (extmake): discard empty Makefile which can be left
  accidentally.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45993 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/ext/extmk.rb b/ext/extmk.rb
index b80a4fc36e..d094891c5f 100755
--- a/ext/extmk.rb
+++ b/ext/extmk.rb
@@ -241,7 +241,7 @@ def extmake(target)
 	$0 = $PROGRAM_NAME
       end
     end
-    ok &&= File.open(makefile){|f| !f.gets[DUMMY_SIGNATURE]}
+    ok &&= File.open(makefile){|f| s = f.gets and !s[DUMMY_SIGNATURE]}
     ok = yield(ok) if block_given?
     if ok
       open(makefile, "r+b") do |f|