Fix assume effects handling for gc_safe (#59557)

Fixes #59552

Author: gbaraldi

base/c.jl

@@ -458,6 +458,6 @@ macro ccall(exprs...)
     return ccall_macro_lower((:ccall), ccall_macro_parse(exprs)...)
 end
 
-macro ccall_effects(effects::UInt16, expr)
-    return ccall_macro_lower((:ccall, effects), ccall_macro_parse(expr)...)
+macro ccall_effects(effects::UInt16, exprs...)
+    return ccall_macro_lower((:ccall, effects), ccall_macro_parse(exprs)...)
 end

test/ccall.jl

@@ -1970,14 +1970,15 @@ end
 
 function gc_safe_ccall()
     # jl_rand is marked as JL_NOTSAFEPOINT
-    @ccall gc_safe=true jl_rand()::UInt64
+    Base.@assume_effects :nothrow @ccall gc_safe=true jl_rand()::UInt64
 end
 
 let llvm = sprint(code_llvm, gc_safe_ccall, ())
     # check that the call works
     @test gc_safe_ccall() isa UInt64
     # check for the gc_safe store
     @test occursin("store atomic i8 2", llvm)
+    @test Base.infer_effects(gc_safe_ccall, Tuple{}).nothrow == true
 end
 
 @testset "jl_dlfind and dlsym" begin