remove the custom compiler driver which hasn't been used in nearly 13 years;
merge scripts/configure and files/Makefile into the port Makefile; replace
a construct that has been deprecated in libpng; respect {C,F,LD}FLAGS [1],
NOPORT{DATA,DOCS,EXAMPLES}, etc.; clean up files/Makefile*; add a test target;
adopt
PR: 161239
Feature safe: yes