diff --git a/bazel/emscripten_toolchain/emar.sh b/bazel/emscripten_toolchain/emar.sh
index e4279f1..b4ead6e 100755
--- a/bazel/emscripten_toolchain/emar.sh
+++ b/bazel/emscripten_toolchain/emar.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
 
-source external/emsdk/emscripten_toolchain/env.sh
+source $(dirname $0)/env.sh
 
 exec python3 $EMSCRIPTEN/emar.py "$@"
diff --git a/bazel/emscripten_toolchain/emcc.sh b/bazel/emscripten_toolchain/emcc.sh
index 7f3699b..5fdaf9c 100755
--- a/bazel/emscripten_toolchain/emcc.sh
+++ b/bazel/emscripten_toolchain/emcc.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
 
-source external/emsdk/emscripten_toolchain/env.sh
+source $(dirname $0)/env.sh
 
 exec python3 $EMSCRIPTEN/emcc.py "$@"
diff --git a/bazel/emscripten_toolchain/emcc_link.sh b/bazel/emscripten_toolchain/emcc_link.sh
index 24d806d..44f3235 100755
--- a/bazel/emscripten_toolchain/emcc_link.sh
+++ b/bazel/emscripten_toolchain/emcc_link.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
 
-source external/emsdk/emscripten_toolchain/env.sh
+source $(dirname $0)/env.sh
 
-exec python3 external/emsdk/emscripten_toolchain/link_wrapper.py "$@"
+exec python3 $(dirname $0)/link_wrapper.py "$@"
diff --git a/bazel/emscripten_toolchain/env.sh b/bazel/emscripten_toolchain/env.sh
index d66a3a1..b2a6bd6 100755
--- a/bazel/emscripten_toolchain/env.sh
+++ b/bazel/emscripten_toolchain/env.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
 
-export ROOT_DIR=`(pwd -P)`
+export ROOT_DIR=${EXT_BUILD_ROOT:-$(pwd -P)}
 export EMSCRIPTEN=$ROOT_DIR/$EM_BIN_PATH/emscripten
 export EM_CONFIG=$ROOT_DIR/$EM_CONFIG_PATH