buildsystem: add configure_package function to finalise package initialisation

config/path

@@ -112,6 +112,7 @@ unset LD_LIBRARY_PATH
   fi
 
   if [ -n "$PKG_DIR" -a -r $PKG_DIR/package.mk ]; then
+    unset -f configure_package
     . $PKG_DIR/package.mk
     [ -z "$PKG_SHORTDESC" ] && PKG_SHORTDESC="$PKG_NAME (autogenerated)"
     [ -z "$PKG_LONGDESC" ] &&  PKG_LONGDESC="$PKG_NAME (autogenerated)"
@@ -208,6 +209,13 @@ if [ "$DISABLE_COLORS" != "yes" ]; then
   endcolor="\e[0m"
 fi
 
+# If sourcing a package, configure any package variables dependent on variables we have set
+if [ -n "$PKG_DIR" -a -r $PKG_DIR/package.mk ]; then
+  if [ "$(type -t configure_package)" = "function" ]; then
+    configure_package
+  fi
+fi
+
 # multilib? nah
 unset CONFIG_SITE
 

scripts/build

@@ -80,6 +80,7 @@ rm -f $STAMP
 setup_toolchain $TARGET
 
 # unset functions
+unset -f configure_package
 unset -f pre_build_target
 unset -f pre_configure_target
 unset -f configure_target
@@ -207,6 +208,11 @@ BOOTSTRAP_MESON_OPTS="$HOST_MESON_OPTS"
 # include buildfile
 . $PKG_DIR/package.mk
 
+# finalise package configuration
+if [ "$(type -t configure_package)" = "function" ]; then
+  configure_package
+fi
+
 if [ "$PKG_IS_KERNEL_PKG" = "yes" ]; then
   if [ "$TARGET_KERNEL_ARCH" = "arm64" -a "$TARGET_ARCH" = "arm" ]; then
     TARGET_PREFIX=$TOOLCHAIN/lib/gcc-linaro-aarch64-linux-gnu/bin/aarch64-linux-gnu-