Make sure the callback functions all have return values.

nufxlib-0/samples/Exerciser.c

@@ -307,6 +307,7 @@ NuResult
 FreeCallback(NuArchive* pArchive, void* args)
 {
     free(args);
+    return kNuOK;
 }
 
 

nufxlib-0/samples/ImgConv.c

@@ -219,6 +219,7 @@ NuResult
 FreeCallback(NuArchive* pArchive, void* args)
 {
     free(args);
+    return kNuOK;
 }
 
 /*
@@ -228,6 +229,7 @@ NuResult
 FcloseCallback(NuArchive* pArchive, void* args)
 {
     fclose((FILE*) args);
+    return kNuOK;
 }
 
 /*

nufxlib-0/samples/Launder.c

@@ -51,6 +51,7 @@ NuResult
 FreeCallback(NuArchive* pArchive, void* args)
 {
     free(args);
+    return kNuOK;
 }
 
 /*

nufxlib-0/samples/TestBasic.c

@@ -98,6 +98,7 @@ NuResult
 FreeCallback(NuArchive* pArchive, void* args)
 {
     free(args);
+    return kNuOK;
 }