Mangling is prevented by using a function instead of a macro for setting
default value of some CPack variables. Function is meant for internal use
in CPack.cmake only.
Old macro is deprecated but kept for backwards compatibility - was
intended for internal use only as it can't be used for CPack after
CPack.cmake script is included.
Patch removes local workarounds that were required by old macro,
fixes default setting of variables that by default inherit value from
another variable that already went through old default setting macro
(e.g. value of CPACK_PACKAGE_INSTALL_REGISTRY_KEY caused error for
wrong escapes if CPACK_PACKAGE_INSTALL_DIRECTORY contained escaped
back slashes) and provides a test for correct escaping of characters.
Roman Donchenko