Keep Leopard compatibility while using the 10.6 SDK

[titer]

Building against the 10.6 SDK causes us to link against newer versions of openssl and curl, and the resulting binary cannot run on 10.5: libcrypto was upgraded from 0.9.7 to 0.9.8, libcurl from 7.16.3 to 7.19.4

Snow Leopard includes libs for backwards compatibility for apps built against the 10.5 SDK, but since the 10.6 SDK only include the headers for the new versions, it does not work the other way.

Possible solutions:

a) Copy headers and libs from the 10.5 SDK into our repo and build/link against it. Advantages: T will then use the system libs, so the package stays the same size. Disadvantages: adds a couple MBs to the repo.

b) Include curl and openssl sources in our repo and build/link them statically. Advantages: lets us use newer versions of the libs. Disadvantages: adds some more MBs to the repo, longer build times, bigger package.

c) Work out some wrapper lib built against the 10.5 SDK that redirects curl/openssl calls to the old versions of the libs. Advantages: same as a), using less space in the repo. Disadvantages: more complex to implement, very slightly slower calls to curl/openssl since it'd go through the wrapper.

Another thread discussing the issue: ​http://www.cocoabuilder.com/archive/message/cocoa/2009/8/28/243749

[titer]

Attached patch for the Xcode project for solution b) For convenience, I uploaded a zip of the 10.5 headers and libs: ​http://eric.lapsus.org/t/leo_libs.zip (just extract it in third-party/)

[titer]

the first patch didn't actually use the right headers...

[livings124]

For reference, the patches above are for option a, not b.

[livings124]

r9053

[livings124]

Of interest to this is #1844