`jl_egal` and `jl_gc_safepoint` are not exported by Julia 1.8.0-beta1

[Taaitaaiger]

These two functions were exported by earlier versions of Julia but are no longer available in the current beta. I tried adding these functions to jl_exported_funcs.inc, but compilation fails if jl_egal is added to this list.

[vtjnash]

Those are macros, so we need to update the tricks somewhat that we use to export them. Used to be just () like this:

julia/src/jlapi.c

Line 462 in 8bdb045

JL_DLLEXPORT void (jl_gc_safepoint)(void)

Now those need an i prefix and to get undef before being defined:

julia/src/julia_internal.h

Lines 426 to 428 in 8bdb045

	#undef jl_svec
	#define jl_svec(n, ...) \
	(ijl_svec)(__extension__({ \