build-linux update

docs/compile/builder-linux/get_toolchains.sh

@@ -7,13 +7,16 @@ EXEDIR="$(cd "$EXEDIR"; pwd)"
 
 BASEURL=https://github.com/bol-van/musl-cross/releases/download/latest
 
+check_prog curl tar xz
+
 [ -d "$TOOLCHAINS" ] || mkdir -p "$TOOLCHAINS"
 
 ask_target 1
 
-pushd "$TOOLCHAINS"
+(
+cd "$TOOLCHAINS"
 for t in $TGT; do
 	[ -d "$t" ] && rm -r "$t"
 	curl -Lo - "${BASEURL}/${t}.tar.xz" | tar -Jx
 done
-popd
+)