Windows - add a DEBUG build with debugging symbols

README.md

@@ -142,6 +142,10 @@ best resource at the moment. This can be viewed at [docs.rs].
   bundled with Microsoft Visual Studio.
 - `cargo-php`'s stub generation feature does not work on Windows. Rewriting this
   functionality to be cross-platform is on the roadmap.
+- To build the application in `DEBUG` mode on Windows,
+  you must have a `PHP SDK` built with the `DEBUG` option enabled
+  and specify the `PHP_LIB` to the folder containing the lib files. 
+  For example: set `PHP_LIB=C:\php-sdk\php-dev\vc16\x64\php-8.3.13-src\x64\Debug_TS`.
 
 [vectorcall]: https://docs.microsoft.com/en-us/cpp/cpp/vectorcall?view=msvc-170
 

windows_build.rs

@@ -23,7 +23,7 @@ impl<'a> Provider<'a> {
     fn get_php_lib_name(&self) -> Result<String> {
         Ok(self
             .devel
-            .php_lib()
+            .php_lib(self.info.debug()?)
             .file_stem()
             .context("Failed to get PHP library name")?
             .to_string_lossy()
@@ -85,7 +85,7 @@ impl<'a> PHPProvider<'a> for Provider<'a> {
         let php_lib_name = self.get_php_lib_name()?;
         let php_lib_search = self
             .devel
-            .php_lib()
+            .php_lib(self.info.debug()?)
             .parent()
             .context("Failed to get PHP library parent folder")?
             .to_string_lossy()
@@ -233,13 +233,46 @@ impl DevelPack {
     }
 
     /// Returns the path of the PHP library containing symbols for linking.
-    pub fn php_lib(&self) -> PathBuf {
-        let php_nts = self.0.join("lib").join("php8.lib");
-        if php_nts.exists() {
-            php_nts
-        } else {
-            self.0.join("lib").join("php8ts.lib")
+    pub fn php_lib(&self, is_debug: bool) -> PathBuf {
+        let php_lib_path = std::env::var("PHP_LIB")
+            .map(PathBuf::from)
+            .unwrap_or_else(|_| self.0.join("lib"));
+
+        if !php_lib_path.exists() {
+            panic!(
+                "Error: Specified PHP library path '{}' does not exist.",
+                php_lib_path.display()
+            );
         }
+
+        let candidates = if is_debug {
+            ["php8_debug.lib", "php8ts_debug.lib"]
+        } else {
+            ["php8.lib", "php8ts.lib"]
+        };
+
+        candidates
+            .iter()
+            .map(|lib| php_lib_path.join(lib))
+            .find(|path| path.exists())
+            .expect(&format!(
+                "{}",
+                if is_debug {
+                    format!(
+                        r#"Error: No suitable PHP library found in '{}'.
+To build the application in DEBUG mode on Windows,
+you must have a PHP SDK built with the DEBUG option enabled
+and specify the PHP_LIB to the folder containing the lib files.
+For example: set PHP_LIB=C:\php-sdk\php-dev\vc16\x64\php-8.3.13-src\x64\Debug_TS."#,
+                        php_lib_path.display()
+                    )
+                } else {
+                    format!(
+                        "Error: No suitable PHP library found in '{}'.",
+                        php_lib_path.display()
+                    )
+                }
+            ))
     }
 
     /// Returns a list of include paths to pass to the compiler.