ISLANDORA-450 Instead of PHP_OS, now using php_uname() for OS detection.

islandora.module

@@ -1873,11 +1873,9 @@ function islandora_islandora_datastream_access($op, AbstractDatastream $datastre
  *   The name of the operating system being used.
  */
 function islandora_os_check() {
-  // Determine if PHP is currently running on Windows. (The constant
-  // "PHP_OS" may return "Windows," "WIN32," "WINNT," "CYGWIN_NT-5.1," etc.)
-  if ((strtolower(substr(PHP_OS, 0, 3)) == 'win') ||
-      (strtolower(substr(PHP_OS, 0, 6)) == 'cygwin')) {
+  // Determine if PHP is currently running on Windows.
+  if (strpos(strtolower(php_uname('s')), 'windows') !== FALSE) {
     return 'Windows';
   }
-  return 'Unix';
+  return 'Linux';
 }