don't add -mavx to CFLAGS if it doesn't work

Fixes compilation on non-x86.

elpa-rpm.patch

@@ -1,6 +1,20 @@
+diff -up mpich/configure.ac.r mpich/configure.ac
+--- mpich/configure.ac.r	2015-03-20 11:03:37.810818537 +0100
++++ mpich/configure.ac	2015-03-20 11:03:41.003835548 +0100
+@@ -215,6 +215,10 @@ dnl first test failed: try again after u
+   [can_compile_avx=yes],
+   [can_compile_avx=no]
+  )
++ if test x"${can_compile_avx}" = x"no" ; then
++  CFLAGS=$save_CFLAGS
++  CXXFLAGS=$save_CXXFLAGS
++ fi
+  fi
+ AC_MSG_RESULT([${can_compile_avx}])
+ 
 diff -up mpich/elpa.pc.in.r mpich/elpa.pc.in
 --- mpich/elpa.pc.in.r	2015-03-16 11:39:51.000000000 +0100
-+++ mpich/elpa.pc.in	2015-03-19 12:42:53.997589760 +0100
++++ mpich/elpa.pc.in	2015-03-20 10:59:37.966517510 +0100
 @@ -9,4 +9,4 @@ Version: @PACKAGE_VERSION@
  URL: @PACKAGE_URL@
  Libs: -L${libdir} -lelpa@SUFFIX@ @LIBS@ @OPENMP_FCFLAGS@
@@ -8,8 +22,8 @@ diff -up mpich/elpa.pc.in.r mpich/elpa.pc.in
 -fcflags= -I${includedir}/elpa@SUFFIX@-@PACKAGE_VERSION@/modules @OPENMP_FCFLAGS@
 +fcflags= -I${libdir}/gfortran/modules @OPENMP_FCFLAGS@
 diff -up mpich/Makefile.am.r mpich/Makefile.am
---- mpich/Makefile.am.r	2015-03-19 12:42:54.002589786 +0100
-+++ mpich/Makefile.am	2015-03-19 12:44:26.025065404 +0100
+--- mpich/Makefile.am.r	2015-03-17 16:05:37.000000000 +0100
++++ mpich/Makefile.am	2015-03-20 10:59:37.967517516 +0100
 @@ -204,47 +204,47 @@ check_SCRIPTS = \
  
  TESTS = $(check_SCRIPTS)

elpa.spec

@@ -4,7 +4,9 @@ Version: 2015.02.002
 Release: 1%{?dist}
 URL: http://elpa.rzg.mpg.de/
 Source0: http://elpa.rzg.mpg.de/elpa-%{version}.tar.gz
-# fix pkgconfig file and use all CPUs for testsuite
+# fix pkgconfig file
+# use all CPUs for testsuite
+# don't add -mavx to CFLAGS if it doesn't work (i.e. on arm)
 Patch1: elpa-rpm.patch
 # build against atlas instead of reference blas
 Patch2: elpa-atlas.patch