diff --git a/configure.ac b/configure.ac
index 59befcca..a5d693a8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -416,7 +416,7 @@ AC_SUBST([LIBTOOL_EXTRA_FLAGS])
 TEST_LDFLAGS=''
 AS_IF([test "x$EMSCRIPTEN" != "x"],[
   EXEEXT=.js
-  TEST_LDFLAGS='--pre-js pre.js'
+  TEST_LDFLAGS='--pre-js pre.js.inc'
 ])
 AC_SUBST(TEST_LDFLAGS)
 
diff --git a/dist-build/emscripten.sh b/dist-build/emscripten.sh
index 49790bfd..3d89835c 100755
--- a/dist-build/emscripten.sh
+++ b/dist-build/emscripten.sh
@@ -1,5 +1,6 @@
 #! /bin/sh
 
+export MAKE_FLAGS='-j4'
 export PREFIX="$(pwd)/libsodium-js"
 export EXPORTED_FUNCTIONS='["_crypto_aead_chacha20poly1305_abytes","_crypto_aead_chacha20poly1305_decrypt","_crypto_aead_chacha20poly1305_encrypt","_crypto_aead_chacha20poly1305_keybytes","_crypto_aead_chacha20poly1305_npubbytes","_crypto_aead_chacha20poly1305_nsecbytes","_crypto_auth","_crypto_auth_bytes","_crypto_auth_keybytes","_crypto_auth_verify","_crypto_box","_crypto_box_detached","_crypto_box_easy","_crypto_box_keypair","_crypto_box_macbytes","_crypto_box_noncebytes","_crypto_box_open","_crypto_box_open_detached","_crypto_box_open_easy","_crypto_box_publickeybytes","_crypto_box_secretkeybytes","_crypto_box_seed_keypair","_crypto_box_seedbytes","_crypto_generichash","_crypto_generichash_bytes","_crypto_generichash_bytes_max","_crypto_generichash_bytes_min","_crypto_generichash_final","_crypto_generichash_init","_crypto_generichash_keybytes","_crypto_generichash_keybytes_max","_crypto_generichash_keybytes_min","_crypto_generichash_update","_crypto_hash","_crypto_hash_bytes","_crypto_scalarmult","_crypto_scalarmult_base","_crypto_scalarmult_bytes","_crypto_scalarmult_scalarbytes","_crypto_secretbox","_crypto_secretbox_detached","_crypto_secretbox_easy","_crypto_secretbox_keybytes","_crypto_secretbox_macbytes","_crypto_secretbox_noncebytes","_crypto_secretbox_open","_crypto_secretbox_open_detached","_crypto_secretbox_open_easy","_crypto_shorthash","_crypto_shorthash_bytes","_crypto_shorthash_keybytes","_crypto_sign","_crypto_sign_bytes","_crypto_sign_detached","_crypto_sign_ed25519_pk_to_curve25519","_crypto_sign_ed25519_sk_to_curve25519","_crypto_sign_keypair","_crypto_sign_open","_crypto_sign_publickeybytes","_crypto_sign_secretkeybytes","_crypto_sign_seed_keypair","_crypto_sign_seedbytes","_crypto_sign_verify_detached","_randombytes","_randombytes_buf","_randombytes_close","_randombytes_random","_randombytes_set_implementation","_randombytes_stir","_randombytes_sysrandom","_randombytes_sysrandom_buf","_randombytes_sysrandom_close","_randombytes_sysrandom_stir","_randombytes_sysrandom_uniform","_randombytes_uniform","_sodium_bin2hex","_sodium_hex2bin","_sodium_init","_sodium_library_version_major","_sodium_library_version_minor","_sodium_memcmp","_sodium_memzero","_sodium_version_string"]'
 export TOTAL_MEMORY=33554432
@@ -8,8 +9,21 @@ export LDFLAGS="-s TOTAL_MEMORY=${TOTAL_MEMORY}"
 
 emconfigure ./configure --enable-minimal --disable-shared --prefix="$PREFIX" \
   CFLAGS="-O3" && \
-emmake make clean &&
-emmake make -j2 install V=1 &&
+emmake make clean && \
+emmake make $MAKE_FLAGS install V=1 && \
 emcc -O3 --closure 1 --llvm-lto 1 $LDFLAGS $JS_EXPORTS_FLAGS \
-  "${PREFIX}/lib/libsodium.a" -o "${PREFIX}/lib/libsodium.js" &&
-emmake make -j2 check V=1
+  "${PREFIX}/lib/libsodium.a" -o "${PREFIX}/lib/libsodium.js" && \
+echo 'Compiling the test suite...' && \
+emmake make $MAKE_FLAGS check > /dev/null 2>&1
+
+echo 'Running the test suite:' && \
+(
+  cd test/default && \
+  for file in *.js; do
+    echo "#! /usr/bin/env node" > "${file}.tmp"
+    fgrep -v '#! /usr/bin/env node' "$file" >> "${file}.tmp"
+    chmod +x "${file}.tmp"
+    mv -f "${file}.tmp" "$file"
+  done
+)
+make $MAKE_FLAGS check && echo 'Done.'
diff --git a/test/default/Makefile.am b/test/default/Makefile.am
index 9434ac39..7608bb71 100644
--- a/test/default/Makefile.am
+++ b/test/default/Makefile.am
@@ -2,6 +2,7 @@
 EXTRA_DIST = \
 	cmptest.h \
 	wintest.bat \
+	pre.js.inc \
 	aead_chacha20poly1305.exp \
 	auth.exp \
 	auth2.exp \
diff --git a/test/default/pre.js b/test/default/pre.js.inc
old mode 100644
new mode 100755
similarity index 100%
rename from test/default/pre.js
rename to test/default/pre.js.inc