Fix MinGW compilation

Author: tstenner

src/loguru/loguru.cpp

@@ -655,7 +655,11 @@ namespace loguru
 
 	const char* home_dir()
 	{
-		#ifdef _WIN32
+        #ifdef __MINGW32__
+            auto home = getenv("USERPROFILE");
+            CHECK_F(home != nullptr, "Missing USERPROFILE");
+            return home;
+        #elif defined(_WIN32)
 			char* user_profile;
 			size_t len;
 			errno_t err = _dupenv_s(&user_profile, &len, "USERPROFILE");