cmake: Install dbgcore.dll if it exists.
cmake: Install dbgcore.dll if it exists.

It seems to be required for the Win10 SDK version of dbghelp.dll

Fixes https://github.com/jrfonseca/drmingw/issues/37

jrfonseca/drmingw,jrfonseca/drmingw,jrfonseca/drmingw,jrfonseca/drmingw