build: use build-locale.sh in all build scripts

contrib/build_locale.sh

@@ -1,7 +1,10 @@
 #!/bin/bash
 
-if [ ! -d "$1" ]; then
-    echo "usage: $0 path/to/locale"
+set -e
+
+if [[ ! -d "$1" || -z "$2" ]]; then
+    echo "usage: $0 locale_source_dir locale_dest_dir"
+    echo "       The dirs can match, to build in place."
     exit 1
 fi
 
@@ -10,7 +13,11 @@ if ! which msgfmt > /dev/null 2>&1; then
     exit 1
 fi
 
-for i in "$1/"*; do
-  mkdir -p "$i/LC_MESSAGES"
-  (msgfmt --output-file="$i/LC_MESSAGES/electrum.mo" "$i/electrum.po" || true)
+cd "$1"
+mkdir -p "$2"
+
+for i in *; do
+    dir="$2/$i/LC_MESSAGES"
+    mkdir -p "$dir"
+    (msgfmt --output-file="$dir/electrum.mo" "$i/electrum.po" || true)
 done