%extend symbols for nested structs get into a wrong C symbol table
test fixed
Add runtime test for %extend and nested union
Merge branch 'wkalinin-csymbols-2' - %extend and nested structs

* wkalinin-csymbols-2:
  Add runtime test for %extend and nested union
  test fixed
  %extend symbols for nested structs get into a wrong C symbol table
CHANGES update