libheif links with libdav1d without declaring a dependency on it

[ryandesign (Ryan Carsten Schmidt)]

$ port -v installed libheif
The following ports are currently installed:
  libheif @1.11.0_0+universal (active) platform='darwin 17' archs='i386 x86_64' date='2021-03-17T04:17:17-0500'
$

$ otool -L /opt/local/bin/heif-convert
/opt/local/bin/heif-convert:
	/opt/local/lib/libheif.1.dylib (compatibility version 13.0.0, current version 13.0.0)
	/opt/local/lib/libde265.0.dylib (compatibility version 2.0.0, current version 2.1.0)
	/opt/local/lib/libx265.192.dylib (compatibility version 192.0.0, current version 192.0.0)
	/opt/local/lib/libdav1d.5.dylib (compatibility version 5.0.0, current version 5.0.0)
	/opt/local/lib/libjpeg.8.dylib (compatibility version 8.0.0, current version 8.2.2)
	/opt/local/lib/libpng16.16.dylib (compatibility version 54.0.0, current version 54.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.50.4)
	/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 400.9.0)
$

$ port rdeps libheif|grep dav1d
$

[MarcusCalhoun-Lopez (Marcus Calhoun-Lopez)]

In 70e4ce26e111e264197f037ad8f64297ac8de986/macports-ports (master):

libheif: add deps to avoid opportunistic linking

Fixes #62542