When trying to build Thunar with '--enable-debug=full', I get the following output: In file included from /usr/include/glib-2.0/glib.h:62:0, from /usr/include/glib-2.0/gobject/gbinding.h:28, from /usr/include/glib-2.0/glib-object.h:23, from /usr/include/glib-2.0/gio/gioenums.h:28, from /usr/include/glib-2.0/gio/giotypes.h:28, from /usr/include/glib-2.0/gio/gio.h:26, from thunar-file.c:53: thunar-file.c: In function ‘thunar_file_reload’: /usr/include/glib-2.0/glib/gmessages.h:576:3: error: ‘return’ with no value, in function returning non-void [-Werror] return; \ ^ ../thunar/thunar-private.h:32:47: note: in expansion of macro ‘g_return_if_fail’ #define _thunar_return_if_fail(expr) g_return_if_fail (expr) ^~~~~~~~~~~~~~~~ thunar-file.c:3923:3: note: in expansion of macro ‘_thunar_return_if_fail’ _thunar_return_if_fail (THUNAR_IS_FILE (file)); ^~~~~~~~~~~~~~~~~~~~~~ thunar-file.c:3921:1: note: declared here thunar_file_reload (ThunarFile *file) ^~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors I have obtained these results on Debian Testing, Fedora 24 and Arch Linux, all of them up-to-date. Building without '--enable-debug' works fine in each case. Please feel free to let me know if/how I can help you fix this.
Fixed in https://git.xfce.org/xfce/thunar/commit/?id=79fdf25f4200015c1808f7bbdfa3b3985381eb40.