$ man 1 pkg_create
...
[b]@pkgdep[/b] [i][file]pkgname[/file][/i]
Declare a dependency on the [i][file]pkgname[/file][/i] package. The [i][file]pkgname[/file][/i] package
must be installed before this package may be installed, and this
package must be deinstalled before the [i][file]pkgname[/file][/i] package is deinâ€
stalled. Multiple [b]@pkgdep[/b] directives may be used if the package
depends on multiple other packages.