Try to find windows resource compiler on PATH as a fallback

In some situations `find_msvc_tool` returns a `Tool` with an empty
environment (without the Windows SDK tools in the PATH).  In that
case, try looking for `rc.exe` on the PATH

Author: lambdageek

compiler/rustc_windows_rc/src/lib.rs

@@ -135,7 +135,9 @@ fn parse_version(version: &str) -> Option<ResourceVersion> {
 /// Find the Windows SDK resource compiler `rc.exe` for the given architecture or target triple.
 /// Returns `None` if the tool could not be found.
 fn find_resource_compiler(arch_or_target: &str) -> Option<path::PathBuf> {
+    // Try to find the tool in a Windows SDK, or fall back to looking for it on the PATH
     find_windows_sdk_tool(arch_or_target, "rc.exe")
+        .or_else(|| env::var_os("PATH").and_then(|p| find_tool_in_path("rc.exe", p)))
 }
 
 /// Find a Windows SDK tool for the given architecture or target triple.