bulk build to use mksh or ksh instead of sh

[Boyd Lynn Gerber <gerberb%zenez.com@localhost>]

Hello,

I'm finding many build failures because of the first line in the files 
using sh.

#!/bin/sh

If it uses either of the 2 below things build.
#!/bin/ksh
#!/usr/pkg/bin/mksh

Is there something I may do to have pkgsrc use either of the above in 
bulk builds instead of the #!/bin/sh

Regards,

--
Boyd Gerber <gerberb%zenez.com@localhost> 801 849-0213
ZENEZ   1042 East Fort Union #135, Midvale Utah  84047