SUBDIRS += $(wildcard fgl)
SUBDIRS += $(wildcard X11)
SUBDIRS += $(wildcard time)
+ifeq "$(Windows)" "NO"
+# HGL is not working on Win32, so omit it for now. Better not to ship it
+# at all than to ship a broken version.
SUBDIRS += $(wildcard HGL)
+endif
SUBDIRS += $(wildcard OpenGL)
SUBDIRS += $(wildcard GLUT)
SUBDIRS += $(wildcard OpenAL)