Linux alternatives for the Windows headers and PerformanceCounter. Some typedefs and #defines for the Linux build. Fixed GetDataDir.

git-svn-id: https://bitcoin.svn.sourceforge.net/svnroot/bitcoin/trunk@23 1a98c847-1fd6-4fd8-948a-caf3550aa51b

util.h

@@ -321,11 +321,19 @@ inline void PrintHex(vector<unsigned char> vch, const char* pszFormat="%s", bool
 {
     printf(pszFormat, HexStr(vch, fSpaces).c_str());
 }
+
 
 inline int64 PerformanceCounter()
 {
-    int64 nCounter = 0;
-    QueryPerformanceCounter((LARGE_INTEGER*)&nCounter);
+    int64 nCounter = 0;
+#ifdef __WXMSW__
+    QueryPerformanceCounter((LARGE_INTEGER*)&nCounter);
+#else
+	// this could be changed to reading /dev/urandom
+	timeval t;
+	gettimeofday(&t, NULL);
+	nCounter += t.tv_sec * 1000000 + t.tv_usec;
+#endif
     return nCounter;
 }