Avoid generating phony dependencies for files that don't exist (#1708)

Author: Rangi42

src/asm/fstack.cpp

@@ -126,20 +126,20 @@ void fstk_SetPreIncludeFile(std::string const &path) {
 	// LCOV_EXCL_STOP
 }
 
+static bool isValidFilePath(std::string const &path) {
+	struct stat statBuf;
+	return stat(path.c_str(), &statBuf) == 0 && !S_ISDIR(statBuf.st_mode); // Reject directories
+}
+
 static void printDep(std::string const &path) {
 	if (dependFile) {
 		fprintf(dependFile, "%s: %s\n", targetFileName.c_str(), path.c_str());
-		if (generatePhonyDeps) {
+		if (generatePhonyDeps && isValidFilePath(path)) {
 			fprintf(dependFile, "%s:\n", path.c_str());
 		}
 	}
 }
 
-static bool isValidFilePath(std::string const &path) {
-	struct stat statBuf;
-	return stat(path.c_str(), &statBuf) == 0 && !S_ISDIR(statBuf.st_mode); // Reject directories
-}
-
 std::optional<std::string> fstk_FindFile(std::string const &path) {
 	for (std::string &incPath : includePaths) {
 		if (std::string fullPath = incPath + path; isValidFilePath(fullPath)) {