diff -u -r ../ruby-2.1.2/lib/mkmf.rb ./lib/mkmf.rb
--- ../ruby-2.1.2/lib/mkmf.rb	2014-02-21 15:14:26.000000000 +0100
+++ ./lib/mkmf.rb	2014-06-26 11:45:44.278140512 +0200
@@ -1825,7 +1825,7 @@
     vpath = $VPATH.dup
     CONFIG["hdrdir"] ||= $hdrdir
     mk << %{
-SHELL = /bin/sh
+SHELL = @TERMUX_PREFIX@/bin/sh
 
 # V=0 quiet, V=1 verbose.  other values don't work.
 V = 0