ccmake: Fix compilation with ncurses on Solaris
On Solaris the ncurses header may define an __attribute__
macro.
This breaks C++ headers that use __attribute__(...)
syntax.
Somehow it causes references to unresolved symbols:
__gthrw_pthread_once
__gthrw_pthread_mutex_lock
__gthrw_pthread_mutex_unlock
instead of references to the correct symbols:
pthread_once
pthread_mutex_lock
pthread_mutex_unlock
Detect this case and undefine the __attribute__
macro after
including the curses headers.