Merge version 0.2.20+ds-2+rpi1 and 0.2.20+ds-4 to produce 0.2.20+ds-4+rpi1

diff --cc debian/changelog
index b68297f9744b0eaa5f687a557571e44c8126b20b,ead262e8990c8e973aaec8a6b42f384ba233451c..c6ac72e6c5c165472e590825142d6d92b053d4ca
--- 1/debian/changelog
--- 2/debian/changelog
+++ b/debian/changelog
@@@ -1,10 -1,23 +1,31 @@@
- openblas (0.2.20+ds-2+rpi1) buster-staging; urgency=medium
++openblas (0.2.20+ds-4+rpi1) buster-staging; urgency=medium
 +
 +  [changes brought forward from 0.2.15-1+rpi1 by Peter Michael Green <plugwash@raspbian.org> at Fri, 11 Mar 2016 23:39:32 +0000]
 +  * Disable arm-gcc-flags.patch which was enforcing gcc flags that are wrong
 +    for raspbian.
 +
-  -- Peter Michael Green <plugwash@raspbian.org>  Mon, 07 Aug 2017 03:57:00 +0000
++ -- Raspbian forward porter <root@raspbian.org>  Wed, 27 Sep 2017 03:09:05 +0000
++
+ openblas (0.2.20+ds-4) unstable; urgency=medium
+ 
+   * Add support for s390x.
+     New patch force-zarch.patch introduced to force the generic build.
+     (Closes: #875618)
+   * Enforce TARGET=POWER6 on ppc64, to avoid FTBFS on some buildds.
+   * Drop obsolete code for -dbgsym migration.
+ 
+  -- Sébastien Villemot <sebastien@debian.org>  Tue, 19 Sep 2017 14:51:23 +0200
+ 
+ openblas (0.2.20+ds-3) unstable; urgency=low
+ 
+   * Multi-archify the package.
+     Incidentally, remove the dependency of libopenblas-dev on libblas-dev, since
+     cblas.h is now managed by the alternative.
+   * Ship openblas.pc in libopenblas-dev.
+   * Improve README.Debian for building a custom package
+   * Bump Standards-Version to 4.1.0.
+ 
+  -- Sébastien Villemot <sebastien@debian.org>  Sat, 09 Sep 2017 10:29:44 +0200
  
  openblas (0.2.20+ds-2) unstable; urgency=medium
  

diff --cc debian/patches/series
Simple merge