Use uintptr_t for hash type; this is consistent with CoreFoundation, which uses
32-bit integers on 32-bit platforms for the hash code, and 64-bit integers on
64-bit platforms. (libheimbase is modelled on CoreFoundation.)
Previously we used unsigned long, which would have the same behavior on
LP32/LP64 systems, but not on Windows (where unsigned long is 32-bits on 64-bit
platforms).
Rename heim_base_atomic_max to heim_base_atomic_integer_max (ditto with _type)
in order to better reflect their usage, now we have a separate
heim_base_atomic() macro for making an atomic version of any type.
As implemented by Jeffrey Altman heim_base_once_f() is a variant of the
"double-checked gate lock pattern". Full memory barriers must be used
when determining whether or not to call SwitchToThread().
Change-Id: I2f8446a56c50a37c921d6e993433c9a3f7488f50
Provide a Windows implementation of heim_base_once that relies upon
InterlockedCompareExchange() and SwitchToThread().
Change-Id: I9cdbda796d1a27fe1e17be63f287b10132858d7f
