Accept Symbol as Function name again

GitHub: fixGH-159
It's used by FFI test. So Symbol may be used by other use cases.
GH-139 introduced the "Function name is String" limitation. This
commit removed the limitation.
Reported by Mamoru TASAKA. Thanks!!!

Author: kou

ext/fiddle/function.c

@@ -154,7 +154,9 @@ initialize(int argc, VALUE argv[], VALUE self)
 if (args[kw_name] !=Qundef) {
 name=args[kw_name];
 #ifdefHAVE_RB_STR_TO_INTERNED_STR
-name=rb_str_to_interned_str(name);
+if (RB_TYPE_P(name, RUBY_T_STRING)) {
+name=rb_str_to_interned_str(name);
+ }
 #endif
  }
 if (args[kw_need_gvl] !=Qundef) {

test/fiddle/test_function.rb

@@ -37,6 +37,11 @@ def test_name
 assert_equal'sin',func.name
 end
 
+deftest_name_symbol
+func=Function.new(@libm['sin'],[TYPE_DOUBLE],TYPE_DOUBLE,name: :sin)
+assert_equal:sin,func.name
+end
+
 deftest_need_gvl?
 ifRUBY_ENGINE == "jruby"
 omit("rb_str_dup() doesn't exist in JRuby")
@@ -261,7 +266,25 @@ def test_no_memory_leak
 
 deftest_ractor_shareable
 omit("Need Ractor")unlessdefined?(Ractor)
-assert_ractor_shareable(Function.new(@libm['sin'],[TYPE_DOUBLE],TYPE_DOUBLE))
+assert_ractor_shareable(Function.new(@libm["sin"],
+[TYPE_DOUBLE],
+TYPE_DOUBLE))
+end
+
+deftest_ractor_shareable_name
+omit("Need Ractor")unlessdefined?(Ractor)
+assert_ractor_shareable(Function.new(@libm["sin"],
+[TYPE_DOUBLE],
+TYPE_DOUBLE,
+name: "sin"))
+end
+
+deftest_ractor_shareable_name_symbol
+omit("Need Ractor")unlessdefined?(Ractor)
+assert_ractor_shareable(Function.new(@libm["sin"],
+[TYPE_DOUBLE],
+TYPE_DOUBLE,
+name: :sin))
 end
 
 private