girepository: Use girepository.symbols for Unix builds too

Rather than having a regex for both builds, but *also* use a symbol
file for the MSVC build which would bitrot quickly, force us to update
the .symbols file by using it for Unix too.

Add some missing symbols.

girepository.symbols

@@ -1,4 +1,3 @@
-/* giarginfo.h */
 g_arg_info_get_closure
 g_arg_info_get_destroy
 g_arg_info_get_direction
@@ -11,8 +10,6 @@ g_arg_info_is_return_value
 g_arg_info_is_skip
 g_arg_info_load_type
 g_arg_info_may_be_null
-
-/* gibaseinfo.h */
 g_base_info_equal
 g_base_info_get_attribute
 g_base_info_get_container
@@ -26,8 +23,7 @@ g_base_info_iterate_attributes
 g_base_info_ref
 g_base_info_unref
 g_info_new
-
-/* gicallableinfo.h */
+g_callable_info_can_throw_gerror
 g_callable_info_get_arg
 g_callable_info_get_caller_owns
 g_callable_info_get_n_args
@@ -35,17 +31,14 @@ g_callable_info_get_return_attribute
 g_callable_info_get_return_type
 g_callable_info_invoke
 g_callable_info_iterate_return_attributes
+g_callable_info_is_method
 g_callable_info_load_arg
 g_callable_info_load_return_type
 g_callable_info_may_return_null
 g_callable_info_skip_return
-
-/* giconstantinfo.h */
 g_constant_info_free_value
 g_constant_info_get_type
 g_constant_info_get_value
-
-/* gienuminfo.h */
 g_enum_info_get_error_domain
 g_enum_info_get_method
 g_enum_info_get_n_methods
@@ -53,24 +46,18 @@ g_enum_info_get_n_values
 g_enum_info_get_storage_type
 g_enum_info_get_value
 g_value_info_get_value
-
-/* gifieldinfo.h */
 g_field_info_get_field
 g_field_info_get_flags
 g_field_info_get_offset
 g_field_info_get_size
 g_field_info_get_type
 g_field_info_set_field
-
-/* gifunctioninfo.h */
 g_function_info_get_flags
 g_function_info_get_property
 g_function_info_get_symbol
 g_function_info_get_vfunc
 g_function_info_invoke
 g_invoke_error_quark
-
-/* giinterfaceinfo.h */
 g_interface_info_find_method
 g_interface_info_find_vfunc
 g_interface_info_get_constant
@@ -86,8 +73,6 @@ g_interface_info_get_n_vfuncs
 g_interface_info_get_property
 g_interface_info_get_signal
 g_interface_info_get_vfunc
-
-/* giobjectinfo.h */
 g_object_info_find_method
 g_object_info_find_method_using_interfaces
 g_object_info_find_signal
@@ -121,18 +106,12 @@ g_object_info_get_type_name
 g_object_info_get_unref_function
 g_object_info_get_unref_function_pointer
 g_object_info_get_vfunc
-
-/* gipropertyinfo.h */
 g_property_info_get_flags
 g_property_info_get_ownership_transfer
 g_property_info_get_type
-
-/* giregisteredtypeinfo.h */
 g_registered_type_info_get_g_type
 g_registered_type_info_get_type_init
 g_registered_type_info_get_type_name
-
-/* girepository.h */
 gi_cclosure_marshal_generic
 g_irepository_dump
 g_irepository_enumerate_versions
@@ -157,8 +136,6 @@ g_irepository_load_typelib
 g_irepository_prepend_search_path
 g_irepository_require
 g_irepository_require_private
-
-/* girffi.h */
 gi_type_info_extract_ffi_return_value
 gi_type_tag_get_ffi_type
 g_callable_info_free_closure
@@ -167,13 +144,9 @@ g_function_info_prep_invoker
 g_function_invoker_destroy
 g_function_invoker_new_for_address
 g_type_info_get_ffi_type
-
-/*gisignalinfo.h */
 g_signal_info_get_class_closure
 g_signal_info_get_flags
 g_signal_info_true_stops_emit
-
-/* gustructinfo.h */
 g_struct_info_find_method
 g_struct_info_get_alignment
 g_struct_info_get_field
@@ -183,8 +156,6 @@ g_struct_info_get_n_methods
 g_struct_info_get_size
 g_struct_info_is_foreign
 g_struct_info_is_gtype_struct
-
-/* gitypeinfo.h */
 g_type_info_is_pointer
 g_type_info_is_zero_terminated
 g_type_info_get_array_fixed_size
@@ -195,8 +166,6 @@ g_type_info_get_param_type
 g_type_info_get_tag
 g_type_tag_to_string
 g_info_type_to_string
-
-/* gitypelib.h */
 g_typelib_check_sanity
 g_typelib_error_quark
 g_typelib_free
@@ -206,8 +175,6 @@ g_typelib_new_from_mapped_file
 g_typelib_new_from_memory
 g_typelib_symbol
 g_typelib_validate
-
-/* giunioninfo.h */
 g_union_info_find_method
 g_union_info_get_alignment
 g_union_info_get_discriminator
@@ -219,8 +186,6 @@ g_union_info_get_n_fields
 g_union_info_get_n_methods
 g_union_info_get_size
 g_union_info_is_discriminated
-
-/* givfuncinfo.h */
 g_vfunc_info_get_address
 g_vfunc_info_get_invoker
 g_vfunc_info_get_flags