Fix source build on aarch64/homebrew

proj-sys/build.rs

@@ -1,6 +1,6 @@
 use flate2::read::GzDecoder;
-use std::fs::File;
 use std::env;
+use std::fs::File;
 use std::path::PathBuf;
 use tar::Archive;
 
@@ -105,6 +105,8 @@ fn build_from_source() -> Result<std::path::PathBuf, Box<dyn std::error::Error>>
         "cargo:rustc-link-search=native={}",
         proj.join("lib").display()
     );
+
+    // This is producing a warning - this directory doesn't exist (on aarch64 anyway)
     println!(
         "cargo:rustc-link-search={}",
         &out_path.join("lib64").display()
@@ -113,9 +115,32 @@ fn build_from_source() -> Result<std::path::PathBuf, Box<dyn std::error::Error>>
         "cargo:rustc-link-search={}",
         &out_path.join("build/lib").display()
     );
+
     // The PROJ library needs SQLite and the C++ standard library.
     println!("cargo:rustc-link-lib=dylib=sqlite3");
+
+    // On platforms like apples aarch64, users are likely to have installed libtiff with homebrew,
+    // which isn't in the default search path, so try to determine path from pkg-config
+    match pkg_config::Config::new()
+        .atleast_version("4.0")
+        .probe("libtiff-4")
+    {
+        Ok(pk) => {
+            eprintln!(
+                "found acceptable libtiff installed at: {:?}",
+                pk.link_paths[0]
+            );
+            println!("cargo:rustc-link-search=native={:?}", pk.link_paths[0]);
+        }
+        Err(err) => {
+            // pkg-config might not even be installed. Let's try to stumble forward
+            // to see if the build succeeds regardless, e.g. if libtiff is installed
+            // in some default search path.
+            eprintln!("Failed to find libtiff with pkg-config: {}", err);
+        }
+    }
     println!("cargo:rustc-link-lib=dylib=tiff");
+
     if cfg!(target_os = "linux") {
         println!("cargo:rustc-link-lib=dylib=stdc++");
     } else if cfg!(target_os = "macos") {