File fix_fs_error.patch of Package openscad

diff '--color=auto' -Naur openscad-2021.01.orig/src/FileModule.cc openscad-2021.01/src/FileModule.cc
--- openscad-2021.01.orig/src/FileModule.cc	2024-05-27 11:57:04.154249159 +0100
+++ openscad-2021.01/src/FileModule.cc	2024-05-27 11:52:36.324609857 +0100
@@ -65,7 +65,7 @@
 	auto ext = fs::path(path).extension().generic_string();
 
 	if (boost::iequals(ext, ".otf") || boost::iequals(ext, ".ttf")) {
-		if (fs::is_regular(path)) {
+		if (fs::is_regular_file(path)) {
 			FontCache::instance()->register_font_file(path);
 		} else {
 			LOG(message_group::Error,Location::NONE,"","Can't read font with path '%1$s'",path);