diff --git a/curspriv.h b/curspriv.h
index f3dc43d4..952fedac 100644
--- a/curspriv.h
+++ b/curspriv.h
@@ -14,13 +14,16 @@ extern "C" {
 #if defined(__TURBOC__) || defined(__EMX__) || defined(__DJGPP__) || \
     defined(PDC_99) || defined(__WATCOMC__)
 # ifndef HAVE_VSSCANF
-#  define HAVE_VSSCANF       /* have vsscanf() */
+#  define HAVE_VSSCANF 1     /* have vsscanf() */
 # endif
 #endif
 
 #if defined(PDC_99) || defined(__WATCOMC__)
+# ifndef HAVE_SNPRINTF
+#  define HAVE_SNPRINTF 1   /* have snprintf() */
+# endif
 # ifndef HAVE_VSNPRINTF
-#  define HAVE_VSNPRINTF     /* have vsnprintf() */
+#  define HAVE_VSNPRINTF 1   /* have vsnprintf() */
 # endif
 #endif
 
diff --git a/demos/nctests.mif b/demos/nctests.mif
index 3d3cfbe5..f967dfdd 100644
--- a/demos/nctests.mif
+++ b/demos/nctests.mif
@@ -1,6 +1,6 @@
 # This provides for compiling and linking the ncurses test programs.
 
-ncurses_testdir = $(HOME)/ncurses-6.1/test
+ncurses_testdir = $(HOME)/ncurses-6.4/test
 
 NCURSES_TESTS   = bs$(E) gdc$(E) hanoi$(E) knight$(E) tclock$(E) \
 lrtest$(E) ncurses$(E)
diff --git a/demos/ncurses_cfg.h b/demos/ncurses_cfg.h
index 4d304842..2b650e7d 100644
--- a/demos/ncurses_cfg.h
+++ b/demos/ncurses_cfg.h
@@ -1,6 +1,6 @@
 /* This file is only used with the ncurses test programs.
  *
- * Have ncurses-6.1 unpacked in your $(HOME) (you don't need to build
+ * Have ncurses-6.4 unpacked in your $(HOME) (you don't need to build
  * it), or edit ncurses_testdir appropriately in the Makefile or
  * nctests.mif. Configure and build PDCurses, and:
  *
@@ -23,7 +23,7 @@
 #define HAVE_UNISTD_H 1
 #define HAVE_TERMATTRS 1
 
-#include <curses.h>
+#include <curspriv.h>
 
 #define ExitProgram exit
 
@@ -45,8 +45,10 @@
 #define HAVE_PUTWIN 1
 #define HAVE_SLK_COLOR 1
 #define HAVE_SLK_INIT 1
+#define HAVE_STRSTR 1
 #define HAVE_USE_DEFAULT_COLORS 1
 #define HAVE_WRESIZE 1
+#define USE_STRING_HACKS 1
 
 #ifdef PDC_WIDE
 # define USE_WIDEC_SUPPORT 1
diff --git a/x11/Makefile.in b/x11/Makefile.in
index 2055d947..7289613c 100644
--- a/x11/Makefile.in
+++ b/x11/Makefile.in
@@ -508,7 +508,7 @@ xmas.o: $(demodir)/xmas.c
 # This section provides for compiling and linking the
 # ncurses test programs.
 
-ncurses_testdir	= $(HOME)/ncurses-6.1/test
+ncurses_testdir	= $(HOME)/ncurses-6.4/test
 
 NCURSES_TESTS	= bs gdc hanoi knight tclock lrtest ncurses