There are some interesting possibilities with Xwoaf and tiny-X, maintained by Puppy forum member goingnuts, re static gui apps.
I have just discovered a GUI toolkit that is written in C, very simple, with a wide range of widgets and possibility of static linking:
...look at the "Guide" in menu in left frame.
I also discovered that a there has been some experimentation with using IUP with BaCon:
Comments:More IUP BaCon discussion Posted on 6 Jun 2017, 17:56 by admin