Linux: restore Platform compilation with GCC 4.4

Move requester defaults into File's constructor for older compilers.
Replace newer string members and select the to_string overload available
in CentOS 6's libstdc++.

src/Platform/File.h

@@ -64,6 +64,9 @@ namespace VeraCrypt
 		File () : FileIsOpen (false), mFileOpenFlags (FlagsNone), SharedHandle (false), FileHandle (0)
 #ifndef TC_WINDOWS
 				,AccTime(0), ModTime (0)
+#endif
+#ifdef TC_LINUX
+				,RequesterBacked (false), ReleaseOnly (false), RequesterUserId (0), RequesterGroupId (0)
 #endif
 		 { }
 		virtual ~File ();
@@ -132,10 +135,10 @@ namespace VeraCrypt
 		bool OpenAsRequester (const FilePath &path, int sysFlags);
 		void RestoreTimestampsAsRequester () const;
 
-		bool RequesterBacked = false;
-		bool ReleaseOnly = false;
-		uid_t RequesterUserId = 0;
-		gid_t RequesterGroupId = 0;
+		bool RequesterBacked;
+		bool ReleaseOnly;
+		uid_t RequesterUserId;
+		gid_t RequesterGroupId;
 #endif
 
 	private:

src/Platform/Unix/Process.cpp

@@ -325,8 +325,8 @@ namespace VeraCrypt
 		bool nixos = false;
 		while (std::getline (contents, line))
 		{
-			if (!line.empty() && line.back() == '\r')
-				line.pop_back();
+			if (!line.empty() && line[line.size() - 1] == '\r')
+				line.erase (line.size() - 1);
 			if (line.compare (0, 3, "ID=") != 0)
 				continue;
 			if (foundId)

src/Platform/Unix/RequesterAccess.cpp

@@ -431,7 +431,7 @@ namespace VeraCrypt
 			return errno;
 
 		// Prepare all allocations before fork; only async-signal-safe calls until exec.
-		const string socketArgument = to_string (sockets[1]);
+		const string socketArgument = to_string (static_cast <long long> (sockets[1]));
 		// AppImage's AppRun supplies the library path used to load this executable.
 		// Preserve that setting only, not the caller's other environment/loader hooks.
 		const char *libraryPath = getenv ("LD_LIBRARY_PATH");