diff --git a/configure/os/CONFIG.Common.win32-x86-cygwin b/configure/os/CONFIG.Common.win32-x86-cygwin
index 2847a2969..92af786a5 100644
--- a/configure/os/CONFIG.Common.win32-x86-cygwin
+++ b/configure/os/CONFIG.Common.win32-x86-cygwin
@@ -17,22 +17,27 @@ EXE=.exe
 
 COMPILER_CPPFLAGS = -D_REENTRANT
 
-ARCH_DEP_CPPFLAGS += -D_X86_
-
 # Set runtime path for shared libraries
 RUNTIME_LDFLAGS = $(SHRLIB_SEARCH_FULLPATHDIRS:%=-Wl,-rpath,%)
 
 # Library used when COMMANDLINE_LIBRARY is READLINE
 LDLIBS_READLINE = -lreadline
 
-#======== THESE 4 LINES MAY NOT BE NECESSARY ===============
-OP_SYS_CPPFLAGS = -D_WIN32=1 -D__WIN32=1 -D__MINGW32__=1 -DWIN32=1 -D__WIN32__=1 -DWINNT=1
-OP_SYS_CPPFLAGS += -U__unix__ -Uunix -U__CYGWIN__ -U__unix -U__CYGWIN32__
-OP_SYS_CPPFLAGS += -D__MSVCRT__
 OP_SYS_CXXFLAGS += -D__cplusplus
 
+# With no-cygwin option:
+#	compiler defines _X86_ 1
+#	compiler defines __MSVCRT__ 1
+#	compiler defines __MINGW32__ 1
+#	compiler defines __WIN32 1
+#	compiler defines __WIN32__ 1
+#	compiler defines _WIN32 1
+#	compiler defines WIN32 1
+#	compiler defines WINNT 1
+#	compiler does not define  __unix __unix__ unix
+#	compiler does not define  __CYGWIN__ __CYGWIN32__
+
 OP_SYS_CPPFLAGS += -mno-cygwin
 OP_SYS_LDFLAGS += -mno-cygwin
 OP_SYS_LDLIBS = -lws2_32 -ladvapi32 -luser32 -lkernel32 -lwinmm
 
-