Add fallback install build for libdmg and cdrkit

Summary: Older version fo cmake do not generate the install target properly.

Test Plan:

make -C ../depends HOST=x86_64-apple-darwin11

Reviewers: #bitcoin_abc, matiu, jasonbcox

Reviewed By: #bitcoin_abc, matiu, jasonbcox

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1242