more travis hackery

Author: geofft

build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("cargo:rustc-cfg=travis");
+}

ci/script.sh

@@ -8,6 +8,8 @@ main() {
         export RUSTFLAGS=--cfg=travis
     fi
 
+    sed -i.bak '/^\[package\]$/ibuild = "build.rs"' Cargo.toml
+
     # Build debug and release targets
     cross build --target $TARGET
     cross build --target $TARGET --release