Fixes some possible warnings (e.g. "warning C4129: 's': unrecognized character escape sequence")
especially on Windows
(cherry picked from commit 849c906014)
* Adds CMAKE_COMMAND and CMAKE_BINARY_DIR to revision_data.h
* Move the source and mysql exe path handling out of the DBUpdater.
* Make some Config methods const for correctness.
* Remove C & CXX flags from revision_data.h
(was unused and didn't capture all cxx vars)
* Reorder the link order to prevent `ld` from ignoring the file
* Ref #15671
(cherry picked from commit 719159e207)
