1 files changed, 1 insertions, 0 deletions
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index 73d1ea8046..0352685f89 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -1822,6 +1822,7 @@ PATH_SEPARATOR = #{CONFIG['PATH_SEPARATOR']}
 VPATH = #{vpath.join(CONFIG['PATH_SEPARATOR'])}
 }
     if $extmk
+      mk << "disthdrdir = #{$nmake ? '{$(VPATH)}' : '$(top_srcdir)/'}\n"
       mk << "RUBYLIB =\n""RUBYOPT = -\n"
     end
     prefix = mkintpath(CONFIG["prefix"])