in V8_0-branch, explicitly state how combining  the use of a
configuration macro interacts with the <SUBSYS>.macroname feature
===GT=== #3822
Merge branch 'V8_0-branch' into V8_1_1-branch
for 8.1.1, state how use of <SUBSYS>.macro prefix interacts with use of the macro
in subsequent macros, which changes for 8.1.1
===GT=== #3822
Merge branch 'V8_1_1-branch'