Apply the arm64 -mpc-relative-literal-loads workaround in configure rather than in debian/rules, to cope with toolchains that don't have the relevant patch applied.

configure.ac

@@ -936,6 +936,21 @@ if test "x$grub_cv_target_cc_qn" = xyes; then
   TARGET_CFLAGS="$TARGET_CFLAGS -Qn"
 fi
 
+if test "x$target_cpu" = xarm64; then
+  # Work around unsupported relocations as reported in
+  # https://lists.gnu.org/archive/html/grub-devel/2015-12/msg00092.html; see
+  # also: https://bugs.launchpad.net/bugs/1533009
+  AC_CACHE_CHECK([whether option -mpc-relative-literal-loads], grub_cv_cc_mpc_relative_literal_loads, [
+    CFLAGS="$TARGET_CFLAGS -mpc-relative-literal-loads -Werror"
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
+		      [grub_cv_cc_mpc_relative_literal_loads=yes],
+		      [grub_cv_cc_mpc_relative_literal_loads=no])
+  ])
+  if test "x$grub_cv_cc_mpc_relative_literal_loads" = xyes; then
+    TARGET_CFLAGS="$TARGET_CFLAGS -mpc-relative-literal-loads"
+  fi
+fi
+
 #
 # Compiler features.
 #

debian/.git-dpm

@@ -1,6 +1,6 @@
 # see git-dpm(1) from git-dpm package
-c9ca44d13eddc6e44de5caa166bda1a89fbddfc0
-c9ca44d13eddc6e44de5caa166bda1a89fbddfc0
+3bae3b8527b938db6413e0d9062c74fe0c0278e7
+3bae3b8527b938db6413e0d9062c74fe0c0278e7
 e8f07821cce1bd0ab6d5622c2a42440f15f4fd71
 e8f07821cce1bd0ab6d5622c2a42440f15f4fd71
 grub2_2.02~beta2.orig.tar.xz

debian/changelog

@@ -1,3 +1,11 @@
+grub2 (2.02~beta2-35) UNRELEASED; urgency=medium
+
+  * Apply the arm64 -mpc-relative-literal-loads workaround in configure
+    rather than in debian/rules, to cope with toolchains that don't have the
+    relevant patch applied.
+
+ -- Colin Watson <cjwatson@debian.org>  Fri, 22 Jan 2016 11:00:44 +0000
+
 grub2 (2.02~beta2-34) unstable; urgency=medium
 
   [ Colin Watson ]

debian/patches/0099-Work-around-unsupported-relocations-on-arm64.patch

@@ -0,0 +1,38 @@
+From 3bae3b8527b938db6413e0d9062c74fe0c0278e7 Mon Sep 17 00:00:00 2001
+From: Colin Watson <cjwatson@debian.org>
+Date: Fri, 22 Jan 2016 10:58:53 +0000
+Subject: Work around unsupported relocations on arm64
+
+The patch for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63304 causes
+the toolchain to emit relocations that GRUB does not support.
+-mpc-relative-literal-loads works around this.
+---
+ configure.ac | 15 +++++++++++++++
+ 1 file changed, 15 insertions(+)
+
+diff --git a/configure.ac b/configure.ac
+index 24b9cbf..010175d 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -936,6 +936,21 @@ if test "x$grub_cv_target_cc_qn" = xyes; then
+   TARGET_CFLAGS="$TARGET_CFLAGS -Qn"
+ fi
+ 
++if test "x$target_cpu" = xarm64; then
++  # Work around unsupported relocations as reported in
++  # https://lists.gnu.org/archive/html/grub-devel/2015-12/msg00092.html; see
++  # also: https://bugs.launchpad.net/bugs/1533009
++  AC_CACHE_CHECK([whether option -mpc-relative-literal-loads], grub_cv_cc_mpc_relative_literal_loads, [
++    CFLAGS="$TARGET_CFLAGS -mpc-relative-literal-loads -Werror"
++    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
++		      [grub_cv_cc_mpc_relative_literal_loads=yes],
++		      [grub_cv_cc_mpc_relative_literal_loads=no])
++  ])
++  if test "x$grub_cv_cc_mpc_relative_literal_loads" = xyes; then
++    TARGET_CFLAGS="$TARGET_CFLAGS -mpc-relative-literal-loads"
++  fi
++fi
++
+ #
+ # Compiler features.
+ #

debian/patches/series

@@ -96,3 +96,4 @@ zfs-hole-birth.patch
 zfs-embedded-data.patch
 zfs-zap-lookup-truncation.patch
 zfs-extensible-dataset-large-blocks.patch
+0099-Work-around-unsupported-relocations-on-arm64.patch

debian/rules

@@ -22,14 +22,6 @@ export HOST_CFLAGS
 export HOST_LDFLAGS
 export TARGET_CPPFLAGS := -Wno-unused-but-set-variable
 
-ifeq ($(DEB_HOST_ARCH),arm64)
-# Work around unsupported relocations as reported in
-# https://lists.gnu.org/archive/html/grub-devel/2015-12/msg00092.html; see
-# also:
-# https://bugs.launchpad.net/bugs/1533009
-export TARGET_CFLAGS := -Os -mpc-relative-literal-loads
-endif
-
 ifeq (,$(shell which qemu-system-i386 2>/dev/null))
 with_check := no
 else