Try more Windows fix?

scripts/build.py

@@ -30,7 +30,12 @@ def protoencode_single(self, name, srcs: Targets, proto, symbol):
         ins=srcs,
         outs=[f"={name}.cc"],
         deps=[r],
-        commands=["$[deps[0]] $[ins] $[outs] " + symbol],
+        commands=[
+            # Materialise symbolic links (for Windows).
+            "cp -L $[ins[0]] $[ins[0]].real",
+            "mv $[ins[0]].real $[ins[0]]",
+            "$[deps[0]] $[ins] $[outs] " + symbol
+        ],
         label="PROTOENCODE",
     )
 

scripts/protoencode.cc

@@ -72,13 +72,7 @@ int main(int argc, const char* argv[])
 {
     PROTO message;
 
-	std::string filename = argv[1];
-	#if defined _WIN32
-		for (char& b : filename)
-			if (b == '/')
-				b = '\\';
-	#endif
-    std::ifstream input(filename);
+    std::ifstream input(argv[1]);
     if (!input)
     {
         perror("couldn't open input file");