* load.c: change s_try_load and s_try_load_path to s_primitive_load

* load.c: change s_try_load and s_try_load_path to s_primitive_load
and s_primitive_load_path.

* eval.c, load.c, error.c (scm_wta): use scm_misc_error.

* error.h: don't declare error symbols.  prototype for scm_misc_error.

* stackchk.c (scm_stack_overflow_key): defined here instead of in
error.c.

* error.c: use SCM_SYMBOL to set up error keys.
scm_misc_error: new procedure.