Move TERMUX_STANDALONE_TOOLCHAIN declaration

See https://github.com/termux/termux-packages/pull/1125

build-package.sh

@@ -292,6 +292,11 @@ termux_step_start_build() {
 	# shellcheck source=/dev/null
 	source "$TERMUX_PKG_BUILDER_SCRIPT"
 
+	TERMUX_STANDALONE_TOOLCHAIN="$TERMUX_TOPDIR/_lib/${TERMUX_NDK_VERSION}-${TERMUX_ARCH}-${TERMUX_PKG_API_LEVEL}"
+	# Bump the below version if a change is made in toolchain setup to ensure
+	# that everyone gets an updated toolchain:
+	TERMUX_STANDALONE_TOOLCHAIN+="-v8"
+
 	if [ -n "${TERMUX_PKG_BLACKLISTED_ARCHES:=""}" ] && [ "$TERMUX_PKG_BLACKLISTED_ARCHES" != "${TERMUX_PKG_BLACKLISTED_ARCHES/$TERMUX_ARCH/}" ]; then
 		echo "Skipping building $TERMUX_PKG_NAME for arch $TERMUX_ARCH"
 		exit 0
@@ -443,11 +448,6 @@ termux_step_host_build() {
 
 # Setup a standalone Android NDK toolchain. Not to be overridden by packages.
 termux_step_setup_toolchain() {
-	TERMUX_STANDALONE_TOOLCHAIN="$TERMUX_TOPDIR/_lib/${TERMUX_NDK_VERSION}-${TERMUX_ARCH}-${TERMUX_PKG_API_LEVEL}"
-	# Bump the below version if a change is made in toolchain setup to ensure
-	# that everyone gets an updated toolchain:
-	TERMUX_STANDALONE_TOOLCHAIN+="-v8"
-
 	# We put this after system PATH to avoid picking up toolchain stripped python
 	export PATH=$PATH:$TERMUX_STANDALONE_TOOLCHAIN/bin