ja_JP locale: Add entry for the new Japanese era [BZ #22964]

The Japanese era name will be changed on May 1, 2019.  The Japanese
government made a preliminary announcement on April 1, 2019.

The glibc ja_JP locale must be updated to include the new era name for
strftime's alternative year format support.

Checked on x86_64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

ChangeLog:

	[BZ #22964]
	* localedata/locales/ja_JP (LC_TIME): Add entry for the new Japanese
	era.
	* time/tst-strftime2.c (dates): Add 2019-04-30 and 2019-05-01.
	(mkreftable): Add rules for the new Japanese era and the new dates.

ChangeLog

@@ -1,3 +1,11 @@
+2019-04-02  TAMUKI Shoichi  <tamuki@linet.gr.jp>
+
+	[BZ #22964]
+	* localedata/locales/ja_JP (LC_TIME): Add entry for the new Japanese
+	era.
+	* time/tst-strftime2.c (dates): Add 2019-04-30 and 2019-05-01.
+	(mkreftable): Add rules for the new Japanese era and the new dates.
+
 2019-04-02  TAMUKI Shoichi  <tamuki@linet.gr.jp>
 	    Rafal Luzynski  <digitalfreak@lingonborough.com>
 

NEWS

@@ -22,6 +22,8 @@ Major new features:
   alternative calendar for the following locales: zh_TW, cmn_TW, hak_TW,
   nan_TW, lzh_TW.
 
+* The entry for the new Japanese era has been added for ja_JP locale.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
 * The functions clock_gettime, clock_getres, clock_settime,

localedata/locales/ja_JP

@@ -14952,7 +14952,7 @@ t_fmt_ampm "%p%I<U6642>%M<U5206>%S<U79D2>"
 %
 % The following dates and their names are recorded below in descending
 % date order (note that <U5E74> or <NEN> follows each date).
-% <HEISEI> -> <SHOWA> -> <TAISHO> -> <MEIJI> -> <AD> -> <BC>
+% <REIWA> -> <HEISEI> -> <SHOWA> -> <TAISHO> -> <MEIJI> -> <AD> -> <BC>
 %
 % Each string is an era description segment with the format:
 % "direction:offset:start_date:end_date:era_name:era_format"
@@ -14964,7 +14964,9 @@ t_fmt_ampm "%p%I<U6642>%M<U5206>%S<U79D2>"
 % - The last entry <U7D00><U5143><U524D> in era_name means BC.
 % - The second-to-last entry <U897F><U66A6> in era_name means AD.
 %
-era	"+:2:1990//01//01:+*:<U5E73><U6210>:%EC%Ey<U5E74>";/
+era	"+:2:2020//01//01:+*:<U4EE4><U548C>:%EC%Ey<U5E74>";/
+	"+:1:2019//05//01:2019//12//31:<U4EE4><U548C>:%EC<U5143><U5E74>";/
+	"+:2:1990//01//01:2019//04//30:<U5E73><U6210>:%EC%Ey<U5E74>";/
 	"+:1:1989//01//08:1989//12//31:<U5E73><U6210>:%EC<U5143><U5E74>";/
 	"+:2:1927//01//01:1989//01//07:<U662D><U548C>:%EC%Ey<U5E74>";/
 	"+:1:1926//12//25:1926//12//31:<U662D><U548C>:%EC<U5143><U5E74>";/

time/tst-strftime2.c

@@ -61,7 +61,9 @@ static const date_t dates[] =
   {  1,  4, 1997 },
   {  1,  4, 1998 },
   {  1,  4, 2010 },
-  {  1,  4, 2011 }
+  {  1,  4, 2011 },
+  { 30,  4, 2019 },
+  {  1,  5, 2019 }
 };
 
 static char ref[array_length (locales)][array_length (formats)]
@@ -91,20 +93,20 @@ mkreftable (void)
   static const int yrj[] =
   {
     43, 44, 45, 2,
-    63, 64, 1, 2, 9, 10, 22, 23
+    63, 64, 1, 2, 9, 10, 22, 23, 31, 1
   };
   /* Buddhist calendar year to be checked.  */
   static const int yrb[] =
   {
     2453, 2454, 2455, 2456,
-    2531, 2532, 2532, 2533, 2540, 2541, 2553, 2554
+    2531, 2532, 2532, 2533, 2540, 2541, 2553, 2554, 2562, 2562
   };
   /* R.O.C. calendar year to be checked.  Negative number is prior to
      Minguo counting up.  */
   static const int yrc[] =
   {
     -2, -1, 1, 2,
-    77, 78, 78, 79, 86, 87, 99, 100
+    77, 78, 78, 79, 86, 87, 99, 100, 108, 108
   };
 
   for (i = 0; i < array_length (locales); i++)
@@ -116,7 +118,8 @@ mkreftable (void)
 	      era = (is_before (k, 30,  7, 1912)) ? "\u660e\u6cbb"
 		  : (is_before (k, 25, 12, 1926)) ? "\u5927\u6b63"
 		  : (is_before (k,  8,  1, 1989)) ? "\u662d\u548c"
-						  : "\u5e73\u6210";
+		  : (is_before (k,  1,  5, 2019)) ? "\u5e73\u6210"
+						  : "\u4ee4\u548c";
 	      yr = yrj[k], sfx = "\u5e74";
 	    }
 	  else if (i == lo_LA)