update vips to 7.42

this commit updates vips to 7.42

Closes #1532.

Signed-off-by: Dominique Orban <dominique.orban@gmail.com>
vips: add 7.42.1 bottle.
R: fixes for gcc build and CLT > 6.0.

- Disable building against Aqua with Xcode/CLT 6.1
- patch for gcc to build correctly against Accelerate.

Fixes #1304.
r: update 3.1.2_1 bottle.