diff --git a/scripts/linux/build-all b/scripts/linux/build-all
index 8582c62a..3930e1e7 100755
--- a/scripts/linux/build-all
+++ b/scripts/linux/build-all
@@ -1,23 +1,25 @@
 #!/usr/bin/env bash
 set -e
-if [ -z "$O3" ]; then
+set -u
+if [ -z "${O3:-}" ]; then
     echo O3 var must point to ovpn3 tree ; exit 1
 fi
-export DEP_DIR=${DEP_DIR:-$HOME/linux}
-export TARGET=${TARGET:-linux}
-cd $DEP_DIR
+export DEP_DIR="${DEP_DIR:-$HOME/linux}"
+export TARGET="${TARGET:-linux}"
+cd "$DEP_DIR"
 rm -rf asio* boost* lz4* lzo* minicrypto openssl* polarssl* snappy*
 echo "******* ASIO"
-$O3/core/deps/asio/build-asio
+"$O3"/core/deps/asio/build-asio
 echo "******* xxHash"
-$O3/core/deps/xxHash/build-xxHash
-echo "******* MBEDTLS"
-$O3/core/scripts/linux/build-mbedtls
+"$O3"/core/deps/xxHash/build-xxHash
+if [ "${MTLS:-1}" = 0 ] ; then
+    echo "******* MBEDTLS (skipped)"
+else
+    echo "******* MBEDTLS"
+    "$O3"/core/scripts/linux/build-mbedtls
+fi
 echo "******* LZ4"
-$O3/core/scripts/linux/build-lz4
+"$O3"/core/scripts/linux/build-lz4
 
 #$O3/core/scripts/linux/build-openssl x64
 #$O3/core/scripts/linux/build-lzo
-#$O3/core/scripts/linux/build-boost
-#$O3/core/scripts/linux/build-snappy
-#$O3/core/scripts/linux/consolidate-so
diff --git a/scripts/mac/build-all b/scripts/mac/build-all
index 089af63a..918131f7 100755
--- a/scripts/mac/build-all
+++ b/scripts/mac/build-all
@@ -1,41 +1,36 @@
 #!/usr/bin/env bash
 set -e
-export DEP_DIR=${DEP_DIR:-$HOME/src/mac}
-if [ -z "$O3" ]; then
+set -u
+export DEP_DIR="${DEP_DIR:-$HOME/src/mac}"
+if [ -z "${O3:-}" ]; then
     echo O3 var must point to ovpn3 tree ; exit 1
 fi
 cd $DEP_DIR
 rm -rf asio* boost* lz4* lzo* minicrypto openssl* polarssl* mbedtls* snappy* jsoncpp*
 
 echo "******* ASIO"
-$O3/core/deps/asio/build-asio
+"$O3"/core/deps/asio/build-asio
 
-if [ "$MTLS" = 0 ] ; then
+if [ "${MTLS:-1}" = 0 ] ; then
     echo "******* MBEDTLS (skipped)"
 else
     echo "******* MBEDTLS"
 
     # consider OSX_SERVER=0
-    $O3/core/scripts/mac/build-mbedtls
+    "$O3"/core/scripts/mac/build-mbedtls
 fi
 
-if [ "$OSSL" = 1 ] ; then
+if [ "${OSSL:-0}" = 1 ] ; then
     echo "******* OPENSSL"
-    $O3/core/scripts/mac/build-openssl
+    "$O3"/core/scripts/mac/build-openssl
 else
     echo "******* OPENSSL  (skipped)"
 fi
 
 echo "******* LZ4"
-$O3/core/scripts/mac/build-lz4
+"$O3"/core/scripts/mac/build-lz4
 echo "******* xxHash"
-$O3/core/deps/xxHash/build-xxHash
+"$O3"/core/deps/xxHash/build-xxHash
 
 echo "******* JSONCPP"
-$O3/core/scripts/mac/build-jsoncpp
-
-
-#echo "******* MINICRYPTO"
-#$O3/core/scripts/mac/build-minicrypto
-#echo "******* SNAPPY"
-#$O3/core/scripts/mac/build-snappy
+"$O3"/core/scripts/mac/build-jsoncpp