Bug 1489092: Handle return value of append() to suppress warnings;r=aklotz

Differential Revision: https://phabricator.services.mozilla.com/D5139

--HG--
extra : moz-landing-system : lando

mozglue/build/WindowsDllBlocklist.cpp

@@ -796,22 +796,22 @@ DllBlocklist_Initialize(uint32_t aInitFlags)
 
     pProc = (void*)GetProcAddress(hKernel, "LoadLibraryA");
     if (pProc) {
-      gStartAddressesToBlock->append(pProc);
+      Unused << gStartAddressesToBlock->append(pProc);
     }
 
     pProc = (void*)GetProcAddress(hKernel, "LoadLibraryW");
     if (pProc) {
-      gStartAddressesToBlock->append(pProc);
+      Unused << gStartAddressesToBlock->append(pProc);
     }
 
     pProc = (void*)GetProcAddress(hKernel, "LoadLibraryExA");
     if (pProc) {
-      gStartAddressesToBlock->append(pProc);
+      Unused << gStartAddressesToBlock->append(pProc);
     }
 
     pProc = (void*)GetProcAddress(hKernel, "LoadLibraryExW");
     if (pProc) {
-      gStartAddressesToBlock->append(pProc);
+      Unused << gStartAddressesToBlock->append(pProc);
     }
   }
 #endif