Include path to MagickWand for easier building

Cargo.toml

@@ -8,6 +8,7 @@ repository = "https://github.com/nlfiedler/magick-rust.git"
 readme = "README.md"
 license = "Apache-2.0"
 keywords = ["magickwand", "imagemagick"]
+build = "build.rs"
 
 [dependencies]
 libc = "0.1.8"

build.rs

@@ -0,0 +1,8 @@
+// build.rs
+
+fn main() {
+    // For the sake of easily building and testing on Mac, include the path
+    // to MagickWand. Chances are MagickWand is in /usr/local/lib, or
+    // somewhere else that rustc can find it.
+    println!("cargo:rustc-link-search=native=/usr/local/lib");
+}