add a number of pkgs

- putting package deps and pkgnames in vars/main.yml

tasks/pkgs/choose.yml

@@ -0,0 +1,18 @@
+---
+- name: linux specific
+  block:
+    - ansible.builtin.include_tasks:
+        file: "pkgs/rust.yml"
+      when:
+        - pkgconfig_rust is undefined
+    - name: append to cargopkgs
+      ansible.builtin.set_fact:
+        cargopkgs: "{{ cargopkgs + [ 'choose' ] }}"
+  when:
+    - ansible_os_family != 'Darwin'
+
+- name: append to syspkgs
+  ansible.builtin.set_fact:
+    syspkgs: "{{ syspkgs + [ 'choose-rust' ] }}"
+  when:
+    - ansible_os_family == 'Darwin'