Change msgfmt to produce little-endian .mo files by default.

* gettext-tools/src/msgfmt.c (main): Initialize 'byteswap' so as to
produce little-endian .mo files by default.
* gettext-tools/doc/gettext.texi: Update documentation.
* gettext-tools/doc/msgfmt.texi (--endianness): Likewise.

NEWS

@@ -1,3 +1,6 @@
+* Support for reproducible builds:
+  - msgfmt now produces little-endian .mo files by default.
+
 Version 0.19.7 - December 2015
 
 * Programming languages support:

gettext-tools/doc/gettext.texi

@@ -5325,8 +5325,8 @@ which appears below.
 @cindex magic signature of MO files
 The first two words serve the identification of the file.  The magic
 number will always signal GNU MO files.  The number is stored in the
-byte order of the generating machine, so the magic number really is
-two numbers: @code{0x950412de} and @code{0xde120495}.
+byte order used when the MO file was generated, so the magic number
+really is two numbers: @code{0x950412de} and @code{0xde120495}.
 
 The second word describes the current revision of the file format,
 composed of a major and a minor revision number.  The revision numbers

gettext-tools/doc/msgfmt.texi

@@ -382,14 +382,13 @@ Align strings to @var{number} bytes (default: 1).
 @item --endianness=@var{byteorder}
 @opindex --endianness@r{, @code{msgfmt} option}
 Write out 32-bit numbers in the given byte order.  The possible values are
-@code{big} and @code{little}.  The default depends on the platform, namely
-on the endianness of the CPU.
+@code{big} and @code{little}.  The default is @code{little}.
 
 MO files of any endianness can be used on any platform.  When a MO file has
 an endianness other than the platform's one, the 32-bit numbers from the MO
 file are swapped at runtime.  The performance impact is negligible.
 
-This option can be useful to produce MO files that are independent of the
+This option can be useful to produce MO files that are optimized for one
 platform.
 
 @item --no-hash

gettext-tools/src/msgfmt.c

@@ -251,6 +251,7 @@ main (int argc, char *argv[])
 
   /* Set default value for global variables.  */
   alignment = DEFAULT_OUTPUT_ALIGNMENT;
+  byteswap = 0 ^ ENDIANNESS;
 
   /* Set program name for messages.  */
   set_program_name (argv[0]);