The build procedure did not bother fixing perl and python scripts
when NO_PERL and NO_PYTHON build-time configuration changed.
* jk/rebuild-perl-scripts-with-no-perl-seting-change:
Makefile: have python scripts depend on NO_PYTHON setting
Makefile: simplify by using SCRIPT_{PERL,SH}_GEN macros
Makefile: have perl scripts depend on NO_PERL setting