Back in the days of FPW and FP DOS, I often found myself resorting to the following:

MAIN.PRG

DO Lib1
RETURN
...
PROCEDURE MainProc
   ...

LIB1.PRG

* library setup code
DO Lib2
* library cleanup code
RETURN

* Procedures and UDFs in Lib1

LIB2.PRG

* library setup code
DO MainProc
* library cleanup code
RETURN

* Procedures and UDFs in Lib2

The downside being that I was chewing up call levels with each library I was adding. You might say that I should just simply append the LIB1.PRG and LIB2.PRG, but in most of these cases, LIB1 and LIB2 were actually .APP files (I needed to be able to replace these libraries w/o recompiling the main .EXE).