Disable Erasure Code xlator if MMX is missing

Erasure Code xlator requires MMX instruction set.
Disable building it if MMX is missing.

BUG: 764655
Change-Id: Id9fe87db33e00c5630c1f3633ebd50fc4ebaec4d
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/8366
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

configure.ac

@@ -323,6 +323,9 @@ AC_CHECK_LIB([readline], [rl_do_undo], [RL_UNDO="yes"], [RL_UNDO="no"])
 
 AC_CHECK_LIB([intl], [gettext])
 
+dnl Erasure Code xlator requires MMX instruction set
+AC_CHECK_HEADERS([xmmintrin.h], [enable_ec_xlator=yes], [enable_ec_xlator=no])
+
 AC_CHECK_HEADERS([sys/xattr.h])
 
 AC_CHECK_HEADERS([sys/ioctl.h], AC_DEFINE(HAVE_IOCTL_IN_SYS_IOCTL_H, 1, [have sys/ioctl.h]))
@@ -449,6 +452,14 @@ fi
 AC_SUBST(FUSERMOUNT_SUBDIR)
 #end FUSERMOUNT section
 
+# Erasure Code xlator section
+BUILD_EC_XLATOR=no
+if test "x$enable_ec_xlator" = "xyes" ; then
+   EC_XLATOR_SUBDIR=ec
+   BUILD_EC_XLATOR="yes"
+fi
+AC_SUBST(EC_XLATOR_SUBDIR)
+
 # QEMU_BLOCK section
 
 AC_ARG_ENABLE([qemu-block],
@@ -1079,4 +1090,5 @@ echo "Use syslog           : $USE_SYSLOG"
 echo "XML output           : $BUILD_XML_OUTPUT"
 echo "QEMU Block formats   : $BUILD_QEMU_BLOCK"
 echo "Encryption xlator    : $BUILD_CRYPT_XLATOR"
+echo "Erasure Code xlator  : $BUILD_EC_XLATOR"
 echo

xlators/cluster/Makefile.am

@@ -1,3 +1,3 @@
-SUBDIRS = stripe afr dht ec
+SUBDIRS = stripe afr dht @EC_XLATOR_SUBDIR@
 
 CLEANFILES =