[CMake] Greediness of kwsys regex

[Gregor Jasny]

Hello,

Today I stumbled across funny behavior of string(REGEX REPLACE:

This one would lead to an empty match:
> string(REGEX REPLACE "(.*)" "\\1Proxy.cpp" _out "IConnectionCallback")

This one would match whole "IConnectionCallback"
> string(REGEX REPLACE "(.+)" "\\1Proxy.cpp" _out "IConnectionCallback")

Principle of least surprise makes me expect that both variants (* vs. +) 
either contain the full string or the minimal set: empty for *, first 
character for +.

Could someone please explain what's going on here?

Thanks,
Gregor