bc: needs dependency on ncurses

[ryandesign@…]

bc uses ncurses but does not declare a dependency on it.

$ port contents bc
Port bc contains:
  /opt/local/bin/bc
  /opt/local/bin/dc
  /opt/local/share/info/bc.info
  /opt/local/share/info/dc.info
  /opt/local/share/man/man1/bc.1.gz
  /opt/local/share/man/man1/dc.1.gz
$ otool -L /opt/local/bin/bc
/opt/local/bin/bc:
	/usr/lib/libedit.2.dylib (compatibility version 2.0.0, current version 2.11.0)
	/opt/local/lib/libncurses.5.dylib (compatibility version 5.0.0, current version 5.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.11)
$ port deps bc
bc @1.06_1+universal has no dependencies.

[ryandesign@…]

Looks like ncurses was only used because of libedit. Now that there's a readline variant, it makes sense to have a libedit variant as well to let the user choose between them, and to add the libedit dependency in it. r96275