This patch is borrowed from Debian's patches for plink

Author: Peter Green <plugwash@p10link.net>
Puropose: Fallback to endian.h if all else fails on 64bit machines
Closes: #528659
Forwarded: Shaun Purcell <plink@chgr.mgh.harvard.edu>
License: same as plink itself.
===================================================================
--- plink-1.06.orig/Rsrv.h	2009-05-15 03:35:29.000000000 +0100
+++ plink-1.06/Rsrv.h	2009-05-15 03:35:41.000000000 +0100
@@ -313,7 +313,18 @@
 #define __BIG_ENDIAN__ 1
 #define SWAPEND 1
 #elif ! defined Win32 /* Windows is little-endian is most cases, anywhere else we're stuck */
-#error "Cannot determine endianness. Make sure config.h is included or __{BIG|LITTLE}_ENDIAN__ is defined ."
+  //try endian.h before we finally bail out
+  #include <endian.h>
+  #if __BYTE_ORDER == __LITTLE_ENDIAN
+    #warning using little endian based on information from endian.h
+    #define __LITTLE_ENDIAN__ 1
+  #elif __BYTE_ORDER == __BIG_ENDIAN
+    #warning using big endian based on information from endian.h
+    #define __BIG_ENDIAN__ 1
+    #define SWAPEND 1
+  #else    
+    #error "Cannot determine endianness. Make sure config.h is included or __{BIG|LITTLE}_ENDIAN__ is defined ."
+  #endif    
 #endif
 
 /* FIXME: all the mess below needs more efficient implementation - the current one is so messy to work around alignment problems on some platforms like Sun and HP 9000 */
kages/bison.scm?id=c872b952c527cb42766654d12059d5ea5224ca6c'>commit</a><a href='/guix/diff/gnu/packages/bison.scm?id=c872b952c527cb42766654d12059d5ea5224ca6c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/bison.scm'>
<input type='hidden' name='id' value='c872b952c527cb42766654d12059d5ea5224ca6c'/><input type='hidden' name='showmsg' value='1'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=c872b952c527cb42766654d12059d5ea5224ca6c&amp;showmsg=1'>root</a>/<a href='/guix/log/gnu?id=c872b952c527cb42766654d12059d5ea5224ca6c&amp;showmsg=1'>gnu</a>/<a href='/guix/log/gnu/packages?id=c872b952c527cb42766654d12059d5ea5224ca6c&amp;showmsg=1'>packages</a>/<a href='/guix/log/gnu/packages/bison.scm?id=c872b952c527cb42766654d12059d5ea5224ca6c&amp;showmsg=1'>bison.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/bison.scm?id=c872b952c527cb42766654d12059d5ea5224ca6c'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2018-08-25 16:23:37 +0200'>2018-08-25</span></td><td class='logsubject'><a href='/guix/commit/gnu/packages/bison.scm?id=cf59c62853c079938f3e415a2fb0c5821df7c607'>gnu: Remove bison@2.7.</a></td><td>Marius Bakke</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/packages/bison.scm (bison-2.7): Remove variable.


</td></tr>
<tr class='logheader'><td><span title='2018-06-12 15:06:20 +0200'>2018-06-12</span></td><td class='logsubject'><a href='/guix/commit/gnu/packages/bison.scm?id=ac98b7a96bcd29948bd54a76cf304e3d2d90b6c4'>gnu: bison: Update to 3.0.5.</a></td><td>Tobias Geerinckx-Rice</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/packages/bison.scm (bison): Update to 3.0.5.


</td></tr>
<tr class='logheader'><td><span title='2017-03-30 01:30:16 +0200'>2017-03-30</span></td><td class='logsubject'><a href='/guix/commit/gnu/packages/bison.scm?id=6fd52309b8f52c9bb59fccffac53e029ce94b698'>gnu: Use HTTPS for almost all gnu.org HOME-PAGEs.</a></td><td>Tobias Geerinckx-Rice</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
All HTTP gnu.org (and supported subdomain) HOME-PAGEs changed to HTTPS.


</td></tr>
<tr class='logheader'><td><span title='2016-07-29 17:35:20 +0200'>2016-07-29</span></td><td class='logsubject'><a href='/guix/commit/gnu/packages/bison.scm?id=0160458bf8a2a77a3ec0283b4bb98fb477ed09f9'>gnu: Use define-public to export packages.</a></td><td>David Craven</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/packages/bison.scm (bison): Define public.
* gnu/packages/flex.scm (flex): Define public.
* gnu/packages/pulseaudio.scm (libsndfile, libsamplerate, pulseaudio): Define
public.
* gnu/packages/sdl.scm (sdl, sdl2, libmikmod, sdl-gfx, sdl-image, sdl-mixer,
sdl-net, sdl-ttf): Define public.
* gnu/packages/search.scm (xapian): Remove unnecessary #:export.
* gnu/packages/swig.scm (swig): Define public.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;


</td></tr>