diff --git a/Recipe b/Recipe
index e42593b2..3b65c83b 100644
--- a/Recipe
+++ b/Recipe
@@ -113,6 +113,11 @@
 #      Cygnus/mingw32, whose resource compiler may have less of a
 #      problem with it.
 #
+#  - COMPAT=/DNO_SECUREZEROMEMORY (Windows only)
+#      Disables PuTTY's use of SecureZeroMemory(), which is missing
+#      from some environments' header files.  This is enabled by
+#      default in the Cygwin Makefile.
+#
 #  - XFLAGS=/DTELNET_DEFAULT
 #      Causes PuTTY to default to the Telnet protocol (in the absence
 #      of Default Settings and so on to the contrary). Normally PuTTY
diff --git a/mkfiles.pl b/mkfiles.pl
index c87ae4e6..3786d311 100755
--- a/mkfiles.pl
+++ b/mkfiles.pl
@@ -453,7 +453,7 @@ if (defined $makefiles{'cygwin'}) {
     "# RCINC = --include-dir c:\\cygwin\\include\\\n".
     "\n".
     &splitline("CFLAGS = -mno-cygwin -Wall -O2 -D_WINDOWS -DDEBUG -DWIN32S_COMPAT".
-      " -D_NO_OLDNAMES -DNO_MULTIMON -DNO_HTMLHELP " .
+      " -D_NO_OLDNAMES -DNO_MULTIMON -DNO_HTMLHELP -DNO_SECUREZEROMEMORY " .
 	       (join " ", map {"-I$dirpfx$_"} @srcdirs)) .
 	       "\n".
     "LDFLAGS = -mno-cygwin -s\n".
diff --git a/windows/winmisc.c b/windows/winmisc.c
index e3321b53..c74f1e7a 100644
--- a/windows/winmisc.c
+++ b/windows/winmisc.c
@@ -68,7 +68,7 @@ Filename *filename_deserialise(void *vdata, int maxsize, int *used)
     return filename_from_str(data);
 }
 
-#ifndef __WINE__ /* No SecureZeroMemory in Winelib 1.4 */
+#ifndef NO_SECUREZEROMEMORY
 /*
  * Windows implementation of smemclr (see misc.c) using SecureZeroMemory.
  */
diff --git a/windows/winstuff.h b/windows/winstuff.h
index 985e01a7..cfed0484 100644
--- a/windows/winstuff.h
+++ b/windows/winstuff.h
@@ -75,7 +75,7 @@ struct FontSpec *fontspec_new(const char *name,
 #define BOXRESULT (DLGWINDOWEXTRA + sizeof(LONG_PTR))
 #define DF_END 0x0001
 
-#ifndef __WINE__ /* No SecureZeroMemory in Winelib 1.4 */
+#ifndef NO_SECUREZEROMEMORY
 #define PLATFORM_HAS_SMEMCLR /* inhibit cross-platform one in misc.c */
 #endif