diff --git a/config.sub b/config.sub
index ba37cf99e2..d772f33065 100755
--- a/config.sub
+++ b/config.sub
@@ -118,7 +118,8 @@ case $maybe_os in
   linux-musl* | linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | \
   knetbsd*-gnu* | netbsd*-gnu* | netbsd*-eabi* | \
   kopensolaris*-gnu* | cloudabi*-eabi* | \
-  storm-chaos* | os2-emx* | rtmk-nova*)
+  storm-chaos* | os2-emx* | rtmk-nova* | \
+  emscripten)
     os=-$maybe_os
     basic_machine=`echo "$1" | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
     ;;
@@ -377,6 +378,7 @@ case $basic_machine in
 	| alpha64-* | alpha64ev[4-8]-* | alpha64ev56-* | alpha64ev6[78]-* \
 	| alphapca5[67]-* | alpha64pca5[67]-* | arc-* | arceb-* \
 	| arm-*  | armbe-* | armle-* | armeb-* | armv*-* \
+  | asmjs \
 	| avr-* | avr32-* \
 	| ba-* \
 	| be32-* | be64-* \
@@ -1522,6 +1524,8 @@ case $os in
 			;;
 		esac
 		;;
+	-emscripten)
+		;;
 	-nacl*)
 		;;
 	-ios)
diff --git a/configure b/configure
index e0389649ae..e6ab1613cf 100755
--- a/configure
+++ b/configure
@@ -3257,6 +3257,9 @@ then
 	*-*-cygwin*)
 		ac_sys_system=Cygwin
 		;;
+	asmjs-*-*)
+		ac_sys_system=Emscripten
+		;;
 	*)
 		# for now, limit cross builds to known configurations
 		MACHDEP="unknown"
@@ -3301,6 +3304,9 @@ if test "$cross_compiling" = yes; then
 	*-*-cygwin*)
 		_host_cpu=
 		;;
+	asmjs-*-*)
+		_host_cpu=
+		;;
 	*)
 		# for now, limit cross builds to known configurations
 		MACHDEP="unknown"
diff --git a/configure.ac b/configure.ac
index b5beb08574..8051e5a8ed 100644
--- a/configure.ac
+++ b/configure.ac
@@ -379,6 +379,9 @@ then
 	*-*-cygwin*)
 		ac_sys_system=Cygwin
 		;;
+	asmjs-*-*)
+		ac_sys_system=Emscripten
+		;;
 	*)
 		# for now, limit cross builds to known configurations
 		MACHDEP="unknown"
@@ -423,6 +426,9 @@ if test "$cross_compiling" = yes; then
 	*-*-cygwin*)
 		_host_cpu=
 		;;
+	asmjs-*-*)
+		_host_cpu=
+		;;
 	*)
 		# for now, limit cross builds to known configurations
 		MACHDEP="unknown"