Fixed some g++ compile issues

src/utils/guid.h

@@ -2,7 +2,7 @@
 #define _guid_h_
 
 #include <string>
-#include "types.h"
+#include "../types.h"
 #include "valuearray.h"
 
 struct FCEU_Guid : public ValueArray<uint8,16>
@@ -15,4 +15,4 @@ struct FCEU_Guid : public ValueArray<uint8,16>
 };
 
 
-#endif
+#endif

src/utils/valuearray.h

@@ -17,4 +17,5 @@ struct ValueArray
 	}
 };
 
-#endif
+#endif
+

src/utils/xstring.cpp

@@ -478,9 +478,39 @@ unsigned int uintDecFromIstream(std::istream* is)
 	is->unget();
 	return ret;
 }
-
+
+//FIXME: itoa isn't ANSI C compliant.  Perhaps sprintf would be better here?   
+#ifdef WIN32
 std::string stditoa(int n)
 {
 	char tempbuf[16];
 	return itoa(n,tempbuf,10);
-}
+}
+#else
+std::string stditoa(int n) {
+	enum { kMaxDigits = 35 };
+	
+	std::string buf;
+	
+	buf.reserve( kMaxDigits ); // Pre-allocate enough space.
+	
+	int quotient = n;
+
+	// Translating number to string with base
+	do {
+		buf += "0123456789abcdef"[ std::abs( quotient % 10 ) ];
+		quotient /= 10;
+	} while ( quotient );
+	
+
+	
+	// Append the negative sign for base 10
+	if ( n < 0) buf += '-';
+	
+	std::reverse( buf.begin(), buf.end() );
+	
+	return buf;
+}
+#endif
+
+