Added SetStrv to glib.settings

[okelet]

Implement SetStrv, but doesn't compile. Please help fix. The documentation of the function is here https://developer.gnome.org/gio/stable/GSettings.html#g-settings-set-strv. I have opened a question in StackOverflow (https://stackoverflow.com/questions/47907238/convert-glib-c-method-with-string-array-as-parameter-to-go), but nobody answered. I don't have enough knowledge of C to do this.

[tommyshem]

Looking at the code in gtk.go from line 6550 they have used this code to create a C string array.
I have have changed your code with the way it is done in gtk.go above.
Not tested as I do not program in cgo, and I do not use this function.
You could try and see if it helps.

// SetStrv is a wrapper around g_settings_set_strv().
func (v *Settings) SetStrv(name string, values []string) bool {
	cstr1 := (*C.gchar)(C.CString(name))
	defer C.free(unsafe.Pointer(cstr1))

	// cvalues := C.make_strings(C.int(len(values) + 1))
	cvalues := make([]*C.gchar, len(values))

	for i, accel := range values {
		cvalues[i] = (*C.gchar)(C.CString(accel))
		defer C.free(unsafe.Pointer(cvalues[i]))
	}
	cvalues = append(cvalues, nil)

	// C.set_string(cvalues, C.int(len(values)), nil)
	return gobool(C.g_settings_set_strv(v.native(), cstr1, &cvalues[0]))

[okelet]

Thanks @tommyshem! Now it compiles, and I have done some tests, and it seems to work. I have commited my forked repo, and the travis build has been relaunched with successful results. The pull is request is now ready and working.

[tommyshem]

@okelet Glad it worked.