diff --git a/GNUmakefile b/GNUmakefile
index 245f10d..4231e0e 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -40,6 +40,9 @@ THREADING = posix
 ifeq ($(GNUSTEP_TARGET_OS),mingw32)
 THREADING = win32
 endif
+ifeq ($(GNUSTEP_TARGET_OS), cygwin)
+THREADING = win32
+endif
 
 GC_HEADER_FILES_DIR = ./gc/include
 GC_HEADER_FILES = \