diff --git a/configure b/configure
index 8682b88f7e0..f2507f7b167 100755
--- a/configure
+++ b/configure
@@ -34539,7 +34539,7 @@ _ACEOF
 
 if test ${use_internal_tzcode} = yes; then
 
-$as_echo "#define USE_INTERNAL_MKTME 1" >>confdefs.h
+$as_echo "#define USE_INTERNAL_MKTIME 1" >>confdefs.h
 
 fi
  if test "x${use_internal_tzcode}" = xyes; then
diff --git a/configure.ac b/configure.ac
index cf99dee1a9d..9fc3ac6bcae 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2274,7 +2274,7 @@ fi
 AC_DEFINE_UNQUOTED(VALGRIND_LEVEL, ${valgrind_level}, [Define as 1 or 2 to specify levels of Valgrind instrumentation])
 
 if test ${use_internal_tzcode} = yes; then
-  AC_DEFINE(USE_INTERNAL_MKTME, 1, [Define to use internal time-zone code])
+  AC_DEFINE(USE_INTERNAL_MKITME, 1, [Define to use internal time-zone code])
 fi
 AM_CONDITIONAL(BUILD_TZONE, [test "x${use_internal_tzcode}" = xyes])
 
diff --git a/doc/NEWS.Rd b/doc/NEWS.Rd
index 49c5bd9637b..9162585a01a 100644
--- a/doc/NEWS.Rd
+++ b/doc/NEWS.Rd
@@ -169,8 +169,15 @@
       are not installed: but recommended packages remain needed for
       thorough checking of an \R build.
       
-      \item (Windows only.)  The version of \samp{tzcode} included in
-      \file{src/extra/tzone} has been updated.
+      \item The version of \samp{tzcode} included in
+      \file{src/extra/tzone} has been updated.  (Formerly used only on
+      Windows.)
+      
+      \item There is experimental support to use the shipped Olson
+      time-zone database and (64-bit) time-zone conversion code: use
+      \command{configure} option \option{--with-internal-tzcode}. (It
+      might be necessary to set environment variable \env{TZ} on OSes
+      where this is not already set.)
     }
   }
 
diff --git a/share/Makefile.in b/share/Makefile.in
index 1a2617bdbe1..7c48885471c 100644
--- a/share/Makefile.in
+++ b/share/Makefile.in
@@ -45,7 +45,7 @@ installdirs:
 	@$(MKINSTALLDIRS) "$(DESTDIR)$(rsharedir)/texmf/tex/latex"
 install-message:
 	@$(ECHO) "installing share ..."
-install-sources: installdirs
+install-sources: installdirs  @BUILD_TZONE_TRUE@ install-zoneinfo
 	@for f in $(srcdir)/R/*.R; do \
 	  $(INSTALL_DATA) $${f} "$(DESTDIR)$(rsharedir)/R"; \
 	done
@@ -78,6 +78,9 @@ install-sources: installdirs
 	done
 install-strip: install
 
+install-zoneinfo:
+	@@R_UNZIPCMD@ -qo $(top_srcdir)/src/extra/tzone/zoneinfo.zip -d "$(DESTDIR)$(rsharedir)"
+
 uninstall:
 	@$(ECHO) "uninstalling share ..."
 	@rm -rf "$(DESTDIR)$(rsharedir)"
diff --git a/src/extra/Makefile.in b/src/extra/Makefile.in
index e84cf902ca9..35d5e951836 100644
--- a/src/extra/Makefile.in
+++ b/src/extra/Makefile.in
@@ -23,8 +23,10 @@ LIBZ =@BUILD_ZLIB_TRUE@ make.zlib
 LIBXDR =@BUILD_XDR_TRUE@ make.xdr
 LIBINTL =@BUILD_LIBINTL_TRUE@ make.intl
 LIBTRE = make.tre
+LIBTZONE = @BUILD_TZONE_TRUE@make.tzone
 LIBXZ =@BUILD_XZ_TRUE@ make.xz
-EXTRAS = $(RBLAS) $(LIBBZ2) $(LIBPCRE) $(LIBZ) $(LIBXDR) $(LIBINTL) $(LIBTRE) $(LIBXZ)
+EXTRAS = $(RBLAS) $(LIBBZ2) $(LIBPCRE) $(LIBZ) $(LIBXDR) $(LIBINTL) \
+  $(LIBTRE) $(LIBTZONE) $(LIBXZ)
 
 all: Makefile R
 
@@ -58,6 +60,9 @@ make.xz: Makefile
 make.intl: Makefile
 	@(cd intl; $(MAKE))
 
+make.tzone: Makefile
+	@(cd tzone; $(MAKE))
+
 
 mostlyclean: clean
 clean:
diff --git a/src/extra/tzone/localtime.c b/src/extra/tzone/localtime.c
index 5228c799deb..6a341d78455 100644
--- a/src/extra/tzone/localtime.c
+++ b/src/extra/tzone/localtime.c
@@ -53,6 +53,7 @@ use of 64-bit time_t irrespective of platform.
 #define localtime R_localtime
 #define mktime R_mktime
 #define tzset R_tzset
+#define tzsetwall R_tzsetwall
 #include <stdint.h>
 typedef int64_t R_time_t;
 #define time_t R_time_t
diff --git a/src/gnuwin32/fixed/h/config.h b/src/gnuwin32/fixed/h/config.h
index 2f1973dc71c..47aa83607c8 100644
--- a/src/gnuwin32/fixed/h/config.h
+++ b/src/gnuwin32/fixed/h/config.h
@@ -835,6 +835,9 @@
 /* Define if you have the 'wint_t' type. (For intl) */
 #define HAVE_WINT_T 1
 
+/* Define if your mktime works correctly outside 1902-2037. */
+#define HAVE_WORKING_64BIT_MKTIME 1
+
 /* Define to 1 if you have cairo. */
 /* #undef HAVE_WORKING_CAIRO */
 
@@ -1031,6 +1034,9 @@
 /* Define to use Apple's ICU. */
 /* #undef USE_ICU_APPLE */
 
+/* Define to use internal time-zone code */
+#define USE_INTERNAL_MKTME 1
+
 /* Define if the POSIX multithreading library can be used. (For intl) */
 /* #undef USE_POSIX_THREADS */
 
diff --git a/src/main/Makefile.in b/src/main/Makefile.in
index b5f2ab80ebe..09ccf1ca9f3 100644
--- a/src/main/Makefile.in
+++ b/src/main/Makefile.in
@@ -88,11 +88,13 @@ R_TRE = ../extra/tre/libtre.a
 R_XDR = @BUILD_XDR_TRUE@ ../extra/xdr/libxdr.a
 R_XZ = @BUILD_XZ_TRUE@  ../extra/xz/liblzma.a
 R_LIBINTL = @BUILD_LIBINTL_TRUE@ ../extra/intl/libintl.a
+R_TZONE = @BUILD_TZONE_TRUE@ ../extra/tzone/localtime.o
 
 MAIN_LIBS = ../unix/libunix.a ../appl/libappl.a ../nmath/libnmath.a
 MAIN_OBJS = `ls ../unix/*.o ../appl/*.o ../nmath/*.o`
 EXTRA_STATIC_LIBS = \
-  $(R_ZLIBS) $(R_BZLIBS) $(R_PCRE) $(R_TRE) $(R_XDR) $(R_XZ) $(R_LIBINTL)
+  $(R_ZLIBS) $(R_BZLIBS) $(R_PCRE) $(R_TRE) $(R_XDR) $(R_XZ) $(R_LIBINTL) \
+  $(R_TZONE)
 STATIC_LIBS = $(MAIN_LIBS) $(EXTRA_STATIC_LIBS)
 
 EXTRA_LIBS = $(BLAS_LIBS) $(FLIBS) $(R_XTRA_LIBS) @LIBINTL@ $(READLINE_LIBS) $(LIBS)
diff --git a/src/main/datetime.c b/src/main/datetime.c
index f73be4ec984..f6a1a7e26de 100644
--- a/src/main/datetime.c
+++ b/src/main/datetime.c
@@ -97,12 +97,12 @@
 #include <errno.h>
 
 #ifdef Win32
-# define USE_INTERNAL_MKTME 1
+# define USE_INTERNAL_MKTIME 1
 #endif
 
 # include <time.h>
 
-#ifdef USE_INTERNAL_MKTME
+#ifdef USE_INTERNAL_MKTIME
 
 # include <stdint.h>
 typedef int64_t R_time_t;
diff --git a/src/main/util.c b/src/main/util.c
index dbb66b92844..48dae37f14e 100644
--- a/src/main/util.c
+++ b/src/main/util.c
@@ -942,7 +942,23 @@ SEXP attribute_hidden do_normalizepath(SEXP call, SEXP op, SEXP args, SEXP rho)
     UNPROTECT(1);
     return ans;
 }
+
+#ifdef USE_INTERNAL_MKTIME
+const char *getTZinfo(void)
+{
+    const char *p = getenv("TZ");
+    if(p) return p;
+#ifdef HAVE_REALPATH
+    static char abspath[PATH_MAX+1] = "";
+    if(!abspath[0] && realpath("/etc/localtime", abspath))
+	return abspath + 20; // strip /usr/share/zoneinfo/
 #endif
+    warning("system timezone name is unknown: set environment variable TZ");
+    return "unknown";
+}
+#endif
+
+#endif // not Win32
 
 
 /* encodeString(x, w, quote, justify) */