instfd: add deb postinst

It appears termux doesn't automatically handle python deps...
Add postinst debscript manually.

tur/instfd/build.sh

@@ -3,6 +3,7 @@ TERMUX_PKG_DESCRIPTION="FreeDOS installed for dosemu2"
 TERMUX_PKG_LICENSE="GPL-3.0"
 TERMUX_PKG_MAINTAINER="@stsp"
 TERMUX_PKG_VERSION=0.3
+TERMUX_PKG_REVISION=1
 TERMUX_PKG_SRCURL=https://github.com/dosemu2/install-freedos/archive/refs/tags/${TERMUX_PKG_VERSION}.tar.gz
 TERMUX_PKG_SHA256=aeade1ec86902df35e0926f802319b625de8fafac33fe834a286b3fe971a086f
 TERMUX_PKG_AUTO_UPDATE=true
@@ -12,3 +13,12 @@ TERMUX_PKG_PYTHON_TARGET_DEPS="tqdm"
 termux_step_make_install() {
 	make -C $TERMUX_PKG_SRCDIR install
 }
+
+termux_step_create_debscripts() {
+	cat <<- EOF > ./postinst
+	#!$TERMUX_PREFIX/bin/sh
+	echo "Installing dependencies through pip. This may take a while..."
+	pip3 install ${TERMUX_PKG_PYTHON_TARGET_DEPS//, / }
+	EOF
+	chmod +x ./postinst
+}