rtld. When _DYNAMIC is referenced normally from C the global offset
table is used implicitly, but newer versions of binutils don't initialize
it statically in the binary, so this doesn't work until rtld is relocated,
which _DYNAMIC is needed for... So, as on other systems with the same
problem, we disassemble a call instruction to _DYNAMIC in order to get
its address.
implementation in case default one provided by rtld is
not suitable.
Consolidate various identical MD lock implementation into
a single file using appropriate machine/atomic.h.
Approved by: re (scottl)
