Comment 3 for bug 736273

> In file included from ../../../src/libCom/cxxTemplates/epicsOnce.cpp:29:0:
>../../../src/libCom/cxxTemplates/epicsSingleton.h:37:5: error: ‘size_t’
> does not name a type

The issue here may be that size_t is only in the std namespace, and so we
need to add "using std :: size_t" or change the declarations to use "std ::
size_t"

> My fix for that was to include
> #include "stddef.h"

In recent codes I prefer including <cstddef> and importing from namespace
std as needed. However, it may be that that header already includes a
standard library header that defines "std :: size_t", and so including
<cstddef> might be superfluous.