Fix MSVC toolchain path_fiddle builds (#10661) 0f0d7c5f81

Our MSVC builds are building with C++latest (instead of C++17), and what that means is that filesystem::path::u8string returns a std::u8string instead of std::string (see https://en.cppreference.com/w/cpp/filesystem/path/string.html), causing a compilation failure for the shader hotload rebuild command. This change adds back in the reinterpret_cast to a char pointer (but still stores the temp string correctly).

Co-authored-by: Josh Jersild <joshua@rive.app>

.rive_head

@@ -1 +1 @@
-0121fd017478dcb91ad60e7f48af043a61e6104f
+0f0d7c5f813080c2fbc0f81e3f17ab6f518799dd

renderer/path_fiddle/path_fiddle.cpp

@@ -856,8 +856,12 @@ void riveMainLoop()
         // windows where the native path character type is wchar_t, then
         // reinterpret_cast the char8_t pointer to char so we can append it to
         // our string.
-        // Store the u8string result to extend its lifetime
-        std::string tempRiveDirStr = tempRiveDir.u8string();
+        // Store the u8string result to extend its lifetime (need to
+        // reinterpret_cast through a const char * pointer because u8string
+        // returns a std::u8string in C++20 and newer, but we need it as a
+        // "char" string)
+        std::string tempRiveDirStr =
+            reinterpret_cast<const char*>(tempRiveDir.u8string().c_str());
 
         std::string rebuildCommand = "sh rebuild_shaders.sh " + tempRiveDirStr;
         std::system(rebuildCommand.c_str());