diff --git a/build-package.sh b/build-package.sh
index ea2b499f58..236b7bdfe1 100755
--- a/build-package.sh
+++ b/build-package.sh
@@ -350,7 +350,7 @@ if [ "$TERMUX_ON_DEVICE_BUILD" = "true" ]; then
 	# Target architecture must be same as for environment used currently.
 	case "$TERMUX_APP_PACKAGE_MANAGER" in
 		"apt") TERMUX_ARCH=$(dpkg --print-architecture);;
-		"pacman") TERMUX_ARCH=$(pacman-conf | grep Architecture | sed 's/Architecture = //g');;
+		"pacman") TERMUX_ARCH=$(pacman-conf Architecture);;
 	esac
 	export TERMUX_ARCH
 fi
diff --git a/scripts/setup-termux.sh b/scripts/setup-termux.sh
index 824f1fe236..426dba3213 100755
--- a/scripts/setup-termux.sh
+++ b/scripts/setup-termux.sh
@@ -18,7 +18,7 @@ PACKAGES+=" asciidoctor"
 PACKAGES+=" autoconf"
 PACKAGES+=" automake"
 PACKAGES+=" bc"
-PACKAGES+=" bison"
+PACKAGES+=" byacc"
 PACKAGES+=" bsdtar"                     # Needed to create pacman packages
 PACKAGES+=" cmake"
 PACKAGES+=" ed"
@@ -45,6 +45,17 @@ PACKAGES+=" valac"
 PACKAGES+=" xmlto"                      # Needed by git's manpage generation
 PACKAGES+=" zip"
 
-apt update
-apt dist-upgrade -y
-apt install -y $PACKAGES
+# Definition of a package manager
+. $(dirname "$(realpath "$0")")/properties.sh
+source "$TERMUX_PREFIX/bin/termux-setup-package-manager" || true
+
+if [ "$TERMUX_APP_PACKAGE_MANAGER" = "apt" ]; then
+	apt update
+	apt dist-upgrade -y
+	apt install -y $PACKAGES
+elif [ "$TERMUX_APP_PACKAGE_MANAGER" = "pacman" ]; then
+	pacman -Syu $PACKAGES --needed --noconfirm
+else
+	echo "Error: no package manager defined"
+	exit 1
+fi