10.7/10.8 compatibility features

README.md

@@ -1,3 +1,9 @@
 # core-foundation-rs
 
 [![Build Status](https://travis-ci.org/servo/core-foundation-rs.svg?branch=master)](https://travis-ci.org/servo/core-foundation-rs)
+
+## Compatibility
+
+By default it targets macOS 10.7.
+
+To enable features added in macOS 10.8, set Cargo feature `mac_os_10_8_features`. To have both 10.8 features and 10.7 compatibility, also set `mac_os_10_7_support`. Setting both requires weak linkage, which is is a nighty-only feature as of Rust 1.19.

core-foundation-sys/Cargo.toml

@@ -10,3 +10,7 @@ build = "build.rs"
 
 [dependencies]
 libc = "0.2"
+
+[features]
+mac_os_10_7_support = [] # backwards compatibility
+mac_os_10_8_features = [] # enables new features

core-foundation/Cargo.toml

@@ -13,3 +13,7 @@ version = "0.4.2"
 
 [dependencies]
 libc = "0.2"
+
+[features]
+mac_os_10_7_support = ["core-foundation-sys/mac_os_10_7_support"] # backwards compatibility
+mac_os_10_8_features = ["core-foundation-sys/mac_os_10_8_features"] # enables new features