Using pkg-config rather than MagickCore-config, to work on FreeBSD

build.rs

@@ -58,7 +58,7 @@ fn main() {
             .arg("--cppflags")
             .output()
     } else {
-        Command::new("MagickCore-config").arg("--cppflags").output()
+        Command::new("pkg-config").args(["--cflags", "--libs", "MagickCore"]).output()
     };
     if let Ok(ok_cppflags) = check_cppflags {
         let cppflags = ok_cppflags.stdout;