-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 @@
+diff -u -r ../ruby-2.4.1/lib/mkmf.rb ./lib/mkmf.rb
+--- ../ruby-2.4.1/lib/mkmf.rb 2017-03-11 19:46:17.000000000 +0100
++++ ./lib/mkmf.rb 2017-08-21 01:04:18.918432148 +0200
+@@ -500,7 +500,7 @@
+ if $universal and (arch_flag = conf['ARCH_FLAG']) and !arch_flag.empty?
+ conf['ARCH_FLAG'] = arch_flag.gsub(/(?:\G|\s)-arch\s+\S+/, '')
+ end
+- RbConfig::expand("$(CPP) #$INCFLAGS #$CPPFLAGS #$CFLAGS #{opt} #{CONFTEST_C} #{outfile}",
++ RbConfig::expand("$(CPP) #$INCFLAGS #$CPPFLAGS #{opt} #{CONFTEST_C} #{outfile}",
+ conf)
+ end
+
+@@ -1894,7 +1894,7 @@
vpath = $VPATH.dup
CONFIG["hdrdir"] ||= $hdrdir
mk << %{
-SHELL = /bin/sh
-+SHELL = /system/bin/sh
++SHELL = @TERMUX_PREFIX@/bin/sh
# V=0 quiet, V=1 verbose. other values don't work.
V = 0