Initialization: set fallback locale as environment variable

The scope of `std::locale::global` appears to be smaller than `setenv("LC_ALL", ...)` and insufficient to fix messed up locale settings for the whole application.

src/util.cpp

@@ -723,18 +723,19 @@ void RenameThread(const char* name)
 
 void SetupEnvironment()
 {
+    std::locale loc("C");
     // On most POSIX systems (e.g. Linux, but not BSD) the environment's locale
     // may be invalid, in which case the "C" locale is used as fallback.
 #if !defined(WIN32) && !defined(MAC_OSX) && !defined(__FreeBSD__) && !defined(__OpenBSD__)
     try {
-        std::locale(""); // Raises a runtime error if current locale is invalid
+        loc = std::locale(""); // Raises a runtime error if current locale is invalid
     } catch (const std::runtime_error&) {
-        std::locale::global(std::locale("C"));
+        setenv("LC_ALL", "C", 1);
     }
 #endif
     // The path locale is lazy initialized and to avoid deinitialization errors 
     // in multithreading environments, it is set explicitly by the main thread.
-    boost::filesystem::path::imbue(std::locale());    
+    boost::filesystem::path::imbue(loc);
 }
 
 void SetThreadPriority(int nPriority)