Fix up leader image paths for existing saves

As a bonus, this also makes the images show up when a save from Windows
is loaded on GNU/Linux or macOS.
It would be particularly useful if Steam Cloud was supported.

src/save_index.cpp

@@ -31,6 +31,8 @@
 #include "filesystem.hpp"
 #include "config.hpp"
 
+#include <boost/algorithm/string/replace.hpp>
+
 static lg::log_domain log_engine("engine");
 #define LOG_SAVE LOG_STREAM(info, log_engine)
 #define ERR_SAVE LOG_STREAM(err, log_engine)
@@ -116,6 +118,7 @@ save_index_class::save_index_class()
 config& save_index_class::data(const std::string& name) {
 	config& cfg = data();
 	if (config& sv = cfg.find_child("save", "save", name)) {
+		fix_leader_image_path(sv);
 		return sv;
 	}
 		config& res = cfg.add_child("save");
@@ -144,6 +147,14 @@ config& save_index_class::data() {
 	return data_;
 }
 
+void save_index_class::fix_leader_image_path(config& data) {
+	for(config& leader : data.child_range("leader")) {
+		std::string leader_image = leader["leader_image"];
+		boost::algorithm::replace_all(leader_image, "\\", "/");
+		leader["leader_image"] = leader_image;
+	}
+}
+
 save_index_class save_index_manager;
 
 class filename_filter {

src/save_index.hpp

@@ -89,6 +89,7 @@ public:
 private:
 	config& data(const std::string& name) ;
 	config& data() ;
+	static void fix_leader_image_path(config& data);
 private:
 	bool loaded_;
 	config data_;