bsd.autotools.mk needs improvement

[Radim Kolar]

I have submited PR ports/67575: freesci. This PR is a perfect example of current $subj flaws. After 2 hours, i have finally found which needs to be set in makefile to get autotools working.

In short:
1) aclocal needs to run before automake. If not run, you can get version mismach errors.
2) AUTOMAKE_ENV should contain correct AUTOCONF=autoconfxxx version from USE_AUTOCONF_VER=xxx
3) CONFIGURE_ENV needs to contain correct versions of autotools for regeneration of Makefiles during build phase. This is needed because for some reason autotools rebuilds them during dependency generation.
CONFIGURE_ENV+= AUTOMAKE=automake17 AUTOCONF=autoconf257 AUTOHEADER=autoheader25
7 ACLOCAL=aclocal17
4) There needs to be phase in bsd.port.mk which allows to patch autotools generated configure script before running it