diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index 54dcf275d55..ae852401eaf 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -43,7 +43,7 @@ GNULIB_MODULES='
   ieee754-h ignore-value intprops largefile libgmp lstat
   malloc-gnu manywarnings memmem-simple mempcpy memrchr memset_explicit
   minmax mkostemp mktime
-  nanosleep nproc nstrftime
+  nanosleep nproc nstrftime-limited
   pathmax pipe2 pselect pthread_sigmask
   qcopy-acl readlink readlinkat realloc-posix regex
   sig2str sigdescr_np socklen stat-time std-gnu11
@@ -58,7 +58,7 @@ GNULIB_MODULES='
 AVOIDED_MODULES='
   access btowc chmod close crypto/af_alg dup fchdir fstat gnulib-i18n
   iswblank iswctype iswdigit iswxdigit langinfo-h libgmp-mpq
-  locale-h localename-unsafe-limited lock
+  localcharset locale-h localename-unsafe-limited lock
   mbrtowc mbsinit memchr mkdir msvc-inval msvc-nothrow nl_langinfo
   openat-die opendir pthread-h raise
   save-cwd select setenv sigprocmask stat stdarg-h
@@ -140,7 +140,11 @@ fi
 
 "$gnulib_srcdir"/gnulib-tool --dir="$src" $GNULIB_TOOL_FLAGS \
 	$avoided_flags $GNULIB_MODULES &&
-rm -- "$src"lib/gl_openssl.h \
+rm -- "$src"lib/calendar-ethiopian.h \
+      "$src"lib/calendar-persian.h \
+      "$src"lib/calendar-thai.h \
+      "$src"lib/calendars.h \
+      "$src"lib/gl_openssl.h \
       "$src"lib/stdio-read.c "$src"lib/stdio-write.c \
       "$src"m4/fcntl-o.m4 \
       "$src"m4/gl-openssl.m4 \
diff --git a/src/conf_post.h b/src/conf_post.h
index 7b6c2bc933b..4a88f46455d 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -380,9 +380,10 @@ extern int emacs_setenv_TZ (char const *);
 # define UNINIT /* empty */
 #endif
 
-/* Emacs does not need glibc strftime behavior for AM and PM
-   indicators.  */
+/* Emacs needs neither glibc strftime behavior for AM and PM indicators,
+   nor Gnulib strftime support for non-Gregorian calendars.  */
 #define REQUIRE_GNUISH_STRFTIME_AM_PM false
+#define SUPPORT_NON_GREG_CALENDARS_IN_STRFTIME false
 
 #ifdef MSDOS
 /* These are required by file-has-acl.c but defined in dirent.h and