support path prefix

Makefile

@@ -318,6 +318,7 @@ define toolchain
                 $(2) \
                 --env UID=$(UID) \
                 --env GID=$(GID) \
+				--env PATH_PREFIX=$(PATH_PREFIX) \
                 --platform=linux/$(ARCH) \
                 --privileged \
                 --cpus $(CPUS) \

scripts/host-env

@@ -5,6 +5,8 @@ uid=${UID?}
 gid=${GID?}
 user=${USER:-"build"}
 export HOME="/home/${user}"
+[ ! -z "$PATH_PREFIX" ] && \
+    export PATH="${PATH_PREFIX}:${PATH}"
 
 # If running user is not root, pivot to custom user/group
 if [ "$uid" != "0" ]; then