diff --git a/ChangeLog b/ChangeLog
index 6e71fff..ca80d40 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,24 @@
 2017-09-19  Rafal Luzynski  <digitalfreak@lingonborough.com>
 
 	[BZ #10871]
+	* locale/C-time.c: Add abbreviated alternative month names, define
+	them as the same as abbreviated month names explicitly.
+	* locale/categories.def: ab_alt_mon and wide-ab_alt_mon added.
+	* locale/langinfo.h: _NL_[W]ABALTMON_1 .. _NL_[W]ABALTMON_12
+	defined.
+	* locale/programs/ld-time.c: Abbreviated alternative month names
+	support added, they are a copy of abmon if not provided
+	explicitly.
+	* locale/programs/locfile-kw.gperf: ab_alt_mon defined.
+	* locale/programs/locfile-token.h: tok_ab_alt_mon defined.
+	* time/strftime_l.c: %Ob (%Oh) format for abbreviated
+	alternative month names added.
+	* time/strptime_l.c: Abbreviated alternative month names also
+	recognized.
+
+2017-09-19  Rafal Luzynski  <digitalfreak@lingonborough.com>
+
+	[BZ #10871]
 	* locale/programs/locfile-kw.h: Regenerated for alt_mon.
 
 2017-09-19  Rafal Luzynski  <digitalfreak@lingonborough.com>
diff --git a/locale/C-time.c b/locale/C-time.c
index ee33652..a03a6d5 100644
--- a/locale/C-time.c
+++ b/locale/C-time.c
@@ -30,7 +30,7 @@ const struct __locale_data _nl_C_LC_TIME attribute_hidden =
   { NULL, },			/* no cached data */
   UNDELETABLE,
   0,
-  135,
+  159,
   {
     { .string = "Sun" },
     { .string = "Mon" },
@@ -166,6 +166,30 @@ const struct __locale_data _nl_C_LC_TIME attribute_hidden =
     { .wstr = (const uint32_t *) L"September" },
     { .wstr = (const uint32_t *) L"October" },
     { .wstr = (const uint32_t *) L"November" },
-    { .wstr = (const uint32_t *) L"December" }
+    { .wstr = (const uint32_t *) L"December" },
+    { .string = "Jan" },
+    { .string = "Feb" },
+    { .string = "Mar" },
+    { .string = "Apr" },
+    { .string = "May" },
+    { .string = "Jun" },
+    { .string = "Jul" },
+    { .string = "Aug" },
+    { .string = "Sep" },
+    { .string = "Oct" },
+    { .string = "Nov" },
+    { .string = "Dec" },
+    { .wstr = (const uint32_t *) L"Jan" },
+    { .wstr = (const uint32_t *) L"Feb" },
+    { .wstr = (const uint32_t *) L"Mar" },
+    { .wstr = (const uint32_t *) L"Apr" },
+    { .wstr = (const uint32_t *) L"May" },
+    { .wstr = (const uint32_t *) L"Jun" },
+    { .wstr = (const uint32_t *) L"Jul" },
+    { .wstr = (const uint32_t *) L"Aug" },
+    { .wstr = (const uint32_t *) L"Sep" },
+    { .wstr = (const uint32_t *) L"Oct" },
+    { .wstr = (const uint32_t *) L"Nov" },
+    { .wstr = (const uint32_t *) L"Dec" }
   }
 };
diff --git a/locale/categories.def b/locale/categories.def
index 53ec8c5..07b19b2 100644
--- a/locale/categories.def
+++ b/locale/categories.def
@@ -249,8 +249,10 @@ DEFINE_CATEGORY
   DEFINE_ELEMENT (_DATE_FMT,                "date_fmt",            opt, string)
   DEFINE_ELEMENT (_NL_W_DATE_FMT,           "wide-date_fmt",       opt,
wstring)
   DEFINE_ELEMENT (_NL_TIME_CODESET,	    "time-codeset",	   std, string)
-  DEFINE_ELEMENT (ALTMON_1,       "alt_mon",       opt, stringarray, 12, 12)
-  DEFINE_ELEMENT (_NL_WALTMON_1,  "wide-alt_mon",  opt, wstringarray, 12, 12)
+  DEFINE_ELEMENT (ALTMON_1,        "alt_mon",         opt, stringarray,  12,
12)
+  DEFINE_ELEMENT (_NL_WALTMON_1,   "wide-alt_mon",    opt, wstringarray, 12,
12)
+  DEFINE_ELEMENT (_NL_ABALTMON_1,  "ab_alt_mon",      opt, stringarray,  12,
12)
+  DEFINE_ELEMENT (_NL_WABALTMON_1, "wide-ab_alt_mon", opt, wstringarray, 12,
12)
   ), NO_POSTLOAD)
 
 
diff --git a/locale/langinfo.h b/locale/langinfo.h
index 78103ce..fb5aaa2 100644
--- a/locale/langinfo.h
+++ b/locale/langinfo.h
@@ -74,7 +74,8 @@ enum
   DAY_7,			/* Saturday */
 #define DAY_7			DAY_7
 
-  /* Abbreviated month names.  */
+  /* Abbreviated month names, in the grammatical form used when the month
+     forms part of a complete date.  */
   ABMON_1,			/* Jan */
 #define ABMON_1			ABMON_1
   ABMON_2,
@@ -176,7 +177,8 @@ enum
   _NL_WDAY_6,		/* Friday */
   _NL_WDAY_7,		/* Saturday */
 
-  /* Abbreviated month names.  */
+  /* Abbreviated month names, in the grammatical form used when the month
+     forms part of a complete date.  */
   _NL_WABMON_1,		/* Jan */
   _NL_WABMON_2,
   _NL_WABMON_3,
@@ -277,6 +279,36 @@ enum
   _NL_WALTMON_11,
   _NL_WALTMON_12,
 
+  /* Abbreviated month names, in the grammatical form used when the month
+     is named by itself.  */
+  _NL_ABALTMON_1,			/* Jan */
+  _NL_ABALTMON_2,
+  _NL_ABALTMON_3,
+  _NL_ABALTMON_4,
+  _NL_ABALTMON_5,
+  _NL_ABALTMON_6,
+  _NL_ABALTMON_7,
+  _NL_ABALTMON_8,
+  _NL_ABALTMON_9,
+  _NL_ABALTMON_10,
+  _NL_ABALTMON_11,
+  _NL_ABALTMON_12,
+
+  /* Abbreviated month names, in the grammatical form used when the month
+     is named by itself.  */
+  _NL_WABALTMON_1,			/* Jan */
+  _NL_WABALTMON_2,
+  _NL_WABALTMON_3,
+  _NL_WABALTMON_4,
+  _NL_WABALTMON_5,
+  _NL_WABALTMON_6,
+  _NL_WABALTMON_7,
+  _NL_WABALTMON_8,
+  _NL_WABALTMON_9,
+  _NL_WABALTMON_10,
+  _NL_WABALTMON_11,
+  _NL_WABALTMON_12,
+
   _NL_NUM_LC_TIME,	/* Number of indices in LC_TIME category.  */
 
   /* LC_COLLATE category: text sorting.
diff --git a/locale/programs/ld-time.c b/locale/programs/ld-time.c
index 0383179..19f01f5 100644
--- a/locale/programs/ld-time.c
+++ b/locale/programs/ld-time.c
@@ -94,6 +94,9 @@ struct locale_time_t
   const char *alt_mon[12];
   const uint32_t *walt_mon[12];
   int alt_mon_defined;
+  const char *ab_alt_mon[12];
+  const uint32_t *wab_alt_mon[12];
+  int ab_alt_mon_defined;
   unsigned char week_ndays;
   uint32_t week_1stday;
   unsigned char week_1stweek;
@@ -664,6 +667,14 @@ time_output (struct localedef_t *locale, const struct
charmap_t *charmap,
   for (n = 0; n < 12; ++n)
     add_locale_wstring (&file, time->walt_mon[n] ?: empty_wstr);
 
+  /* The ab'alt'mons.  */
+  for (n = 0; n < 12; ++n)
+    add_locale_string (&file, time->ab_alt_mon[n] ?: "");
+
+  /* The wide character ab'alt'mons.  */
+  for (n = 0; n < 12; ++n)
+    add_locale_wstring (&file, time->wab_alt_mon[n] ?: empty_wstr);
+
   write_locale_data (output_path, LC_TIME, "LC_TIME", &file);
 }
 
@@ -808,6 +819,7 @@ time_read (struct linereader *ldfile, struct localedef_t
*result,
 	  STRARR_ELEM (am_pm, 2, 2);
 	  STRARR_ELEM (alt_digits, 0, 100);
 	  STRARR_ELEM (alt_mon, 12, 12);
+	  STRARR_ELEM (ab_alt_mon, 12, 12);
 
 	case tok_era:
 	  /* Ignore the rest of the line if we don't need the input of
@@ -968,6 +980,13 @@ time_read (struct linereader *ldfile, struct localedef_t
*result,
 	      memcpy (time->walt_mon, time->wmon, sizeof (time->wmon));
 	      time->alt_mon_defined = 1;
 	    }
+	  /* The same for abbreviated versions.  */
+	  if (!ignore_content && !time->ab_alt_mon_defined)
+	    {
+	      memcpy (time->ab_alt_mon, time->abmon, sizeof (time->abmon));
+	      memcpy (time->wab_alt_mon, time->wabmon, sizeof (time->wabmon));
+	      time->ab_alt_mon_defined = 1;
+	    }
 	  return;
 
 	default:
diff --git a/locale/programs/locfile-kw.gperf b/locale/programs/locfile-kw.gperf
index 3d11cc6..cae0ad8 100644
--- a/locale/programs/locfile-kw.gperf
+++ b/locale/programs/locfile-kw.gperf
@@ -149,6 +149,7 @@ cal_direction,          tok_cal_direction,          0
 timezone,               tok_timezone,               0
 date_fmt,               tok_date_fmt,               0
 alt_mon,                tok_alt_mon,                0
+ab_alt_mon,             tok_ab_alt_mon,             0
 LC_MESSAGES,            tok_lc_messages,            0
 yesexpr,                tok_yesexpr,                0
 noexpr,                 tok_noexpr,                 0
diff --git a/locale/programs/locfile-token.h b/locale/programs/locfile-token.h
index 2a313b2..6631796 100644
--- a/locale/programs/locfile-token.h
+++ b/locale/programs/locfile-token.h
@@ -187,6 +187,7 @@ enum token_t
   tok_timezone,
   tok_date_fmt,
   tok_alt_mon,
+  tok_ab_alt_mon,
   tok_lc_messages,
   tok_yesexpr,
   tok_noexpr,
diff --git a/time/strftime_l.c b/time/strftime_l.c
index 1c4bed8..412012f 100644
--- a/time/strftime_l.c
+++ b/time/strftime_l.c
@@ -106,6 +106,7 @@ extern char *tzname[];
 # define UCHAR_T unsigned char
 # define L_(Str) Str
 # define NLW(Sym) Sym
+# define ABALTMON_1 _NL_ABALTMON_1
 
 # if !defined STDC_HEADERS && !defined HAVE_MEMCPY
 #  define MEMCPY(d, s, n) bcopy ((s), (d), (n))
@@ -492,6 +493,9 @@ __strftime_internal (CHAR_T *s, size_t maxsize, const CHAR_T
*format,
 # define f_month \
   ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11			     \
 		     ? "?" : _NL_CURRENT (LC_TIME, NLW(MON_1) + tp->tm_mon)))
+# define a_altmonth \
+  ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11			     \
+		     ? "?" : _NL_CURRENT (LC_TIME, NLW(ABALTMON_1) + tp->tm_mon)))
 # define f_altmonth \
   ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11			     \
 		     ? "?" : _NL_CURRENT (LC_TIME, NLW(ALTMON_1) + tp->tm_mon)))
@@ -501,6 +505,7 @@ __strftime_internal (CHAR_T *s, size_t maxsize, const CHAR_T
*format,
 
 # define aw_len STRLEN (a_wkday)
 # define am_len STRLEN (a_month)
+# define aam_len STRLEN (a_altmonth)
 # define ap_len STRLEN (ampm)
 #else
 # if !HAVE_STRFTIME
@@ -510,11 +515,13 @@ __strftime_internal (CHAR_T *s, size_t maxsize, const
CHAR_T *format,
 		   ? "?" : month_name[tp->tm_mon])
 #  define a_wkday f_wkday
 #  define a_month f_month
+#  define a_altmonth a_month
 #  define f_altmonth f_month
 #  define ampm (L_("AMPM") + 2 * (tp->tm_hour > 11))
 
   size_t aw_len = 3;
   size_t am_len = 3;
+  size_t aam_len = 3;
   size_t ap_len = 2;
 # endif
 #endif
@@ -779,10 +786,13 @@ __strftime_internal (CHAR_T *s, size_t maxsize, const
CHAR_T *format,
 	      to_uppcase = 1;
 	      to_lowcase = 0;
 	    }
-	  if (modifier != 0)
+	  if (modifier == L_('E'))
 	    goto bad_format;
 #if defined _NL_CURRENT || !HAVE_STRFTIME
-	  cpy (am_len, a_month);
+	  if (modifier == L_('O'))
+	    cpy (aam_len, a_altmonth);
+	  else
+	    cpy (am_len, a_month);
 	  break;
 #else
 	  goto underlying_strftime;
diff --git a/time/strptime_l.c b/time/strptime_l.c
index b99f5d2..7193dc8 100644
--- a/time/strptime_l.c
+++ b/time/strptime_l.c
@@ -126,6 +126,8 @@ extern const struct __locale_data _nl_C_LC_TIME
attribute_hidden;
 # define ab_month_name (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABMON_1)].string)
 # define alt_month_name \
   (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ALTMON_1)].string)
+# define ab_alt_month_name \
+  (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (_NL_ABALTMON_1)].string)
 # define HERE_D_T_FMT (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (D_T_FMT)].string)
 # define HERE_D_FMT (_nl_C_LC_TIME.values[_NL_ITEM_INDEX (D_FMT)].string)
