std::getenv is not supported using uwp

code/Common/ImporterRegistry.cpp

@@ -214,7 +214,12 @@ void GetImporterInstanceList(std::vector<BaseImporter *> &out) {
     // Some importers may be unimplemented or otherwise unsuitable for general use
     // in their current state. Devs can set ASSIMP_ENABLE_DEV_IMPORTERS in their
     // local environment to enable them, otherwise they're left out of the registry.
+#if defined(WINAPI_FAMILY) && WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP
+    // not supported under uwp
     const char *envStr = std::getenv("ASSIMP_ENABLE_DEV_IMPORTERS");
+#else
+    const char *envStr = { "0" };
+#endif
     bool devImportersEnabled = envStr && strcmp(envStr, "0");
 
     // Ensure no unused var warnings if all uses are #ifndef'd away below: