add documentation for cxListClone() - relates to #744

add documentation for cxMapClone() - resolves #743

add tests for cxMapClone() - relates to #743

add destruction of uninitialized entries on allocation failure to cxMapClone() - relates to #743

untested draft of cxMapClone() - relates to #743

add cxListClone() - resolves #744 except for test coverage

fix accidental additions of unnecessary unistd.h includes

(0) -1000 -300 -100 -30 -10 -7 +7 +10 tip

mercurial