Make linking_cc_block_p thread-local. The rest of this module's
variables are initialized by the ASM_INIT_HOOK, part of
compiler_reset, which is called during compiler_initialize (the
singularly threaded boot) or LOAD-BAND (a GC wait).
SCHEME_OBJECT return_to_interpreter;
SCHEME_OBJECT reflect_to_interface;
-static bool linking_cc_block_p = 0;
+static __thread bool linking_cc_block_p = 0;
static SCHEME_OBJECT make_compiler_utilities (void);
static void open_stack_gap (unsigned long, unsigned long);