fix: windows UNICODE incompatibilities with ares_getaddrinfo (#328)

Fixes the following compatibility issues:
* Use RegQueryValueExA instead of RegQueryValueEx
* Use ExpandEnvironmentStringsA instead of ExpandEnvironmentStrings
* Use RegOpenKeyExA instead of RegOpenKeyExA
* Use GetWindowsDirectoryA instead of GetWindowsDirectoryA

Fix By: Shelley Vohr (@codebytere)
Closes: #327

ares_getaddrinfo.c

@@ -456,18 +456,18 @@ static int file_lookup(struct host_query *hquery)
           char tmp[MAX_PATH];
           HKEY hkeyHosts;
 
-          if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
+          if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ,
                            &hkeyHosts) == ERROR_SUCCESS)
             {
               DWORD dwLength = MAX_PATH;
-              RegQueryValueEx(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
+              RegQueryValueExA(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp,
                               &dwLength);
-              ExpandEnvironmentStrings(tmp, PATH_HOSTS, MAX_PATH);
+              ExpandEnvironmentStringsA(tmp, PATH_HOSTS, MAX_PATH);
               RegCloseKey(hkeyHosts);
             }
         }
       else if (platform == WIN_9X)
-        GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
+        GetWindowsDirectoryA(PATH_HOSTS, MAX_PATH);
       else
         return ARES_ENOTFOUND;