fixup! fixup! move gc_safe to cconv field

Author: vchuravy

doc/src/devdocs/llvm.md

@@ -347,7 +347,7 @@ need to make sure that the array does stay alive while we're doing the
 [`ccall`](@ref). To understand how this is done, lets look at a hypothetical
 approximate possible lowering of the above code:
 ```julia
-return $(Expr(:foreigncall, :(:foo), Cvoid, svec(Ptr{Float64}), 0, false, :(:ccall), Expr(:foreigncall, :(:jl_array_ptr), Ptr{Float64}, svec(Any), 0, false, :(:ccall), :(A)), :(A)))
+return $(Expr(:foreigncall, :(:foo), Cvoid, svec(Ptr{Float64}), 0, :(:ccall), Expr(:foreigncall, :(:jl_array_ptr), Ptr{Float64}, svec(Any), 0, :(:ccall), :(A)), :(A)))
 ```
 The last `:(A)`, is an extra argument list inserted during lowering that informs
 the code generator which Julia level values need to be kept alive for the

src/ccall.cpp

@@ -1419,7 +1419,7 @@ const int fc_args_start = 6;
 // Expr(:foreigncall, pointer, rettype, (argtypes...), nreq, gc_safe, [cconv | (cconv, effects)], args..., roots...)
 static jl_cgval_t emit_ccall(jl_codectx_t &ctx, jl_value_t **args, size_t nargs)
 {
-    JL_NARGSV(ccall, 6);
+    JL_NARGSV(ccall, 5);
     args -= 1;
     jl_value_t *rt = args[2];
     jl_value_t *at = args[3];