Try to let it compile on other platforms

Try to let it compile on other platforms
* src/profiler.c (evict_lower_half): Fix typo.
(PROFILER_CPU_SUPPORT): Check and define if cpu-profiler is supported.
Don't compile the cpu-profiler code, if not supported.
(malloc_probe): Presume memory_log is non-nil.
(syms_of_profiler): Don't defsubr functions when they aren't defined.
* src/lisp.h (sample_profiler_running, gc_probe): Don't declare.