FYI: I believe you have to use the flag -gnatn or -gnatN to inline packages with GNAT.
Optimizing your project: https://www.pegasoft.ca/resources/boblap/7.html
GNAT: Alphabetical list of all switches: https://gcc.gnu.org/onlinedocs/gcc-8.2.0/gnat_ugn/Alphabetic...