only enable support for freedreno on arm automatically

Users can still override this by explicitly passing --enable-freedreno
to configure.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@ubuntu.com>
diff --git a/configure.ac b/configure.ac
index c0ab430..8422de9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -95,8 +95,8 @@
 
 AC_ARG_ENABLE(freedreno,
 	      AS_HELP_STRING([--disable-freedreno],
-	      [Enable support for freedreno's KMS API (default: enabled)]),
-	      [FREEDRENO=$enableval], [FREEDRENO=yes])
+	      [Enable support for freedreno's KMS API (default: enabled on arm)]),
+	      [FREEDRENO=$enableval], [FREEDRENO=auto])
 
 AC_ARG_ENABLE(freedreno-kgsl,
 	      AS_HELP_STRING([--enable-freedreno-kgsl],
@@ -277,6 +277,13 @@
 	esac
 fi
 
+if test "x$FREEDRENO" = xauto ; then
+	case $host_cpu in
+		arm*|aarch64)	FREEDRENO="yes" ;;
+		*)		FREEDRENO="no" ;;
+	esac
+fi
+
 AM_CONDITIONAL(HAVE_LIBKMS, [test "x$LIBKMS" = xyes])
 
 AM_CONDITIONAL(HAVE_INTEL, [test "x$INTEL" = xyes])