Use the gold linker for linux/ARM and android/ARM targets.

Fixes #8976 and #9873 by making use of the Binutils ld.gold
linker explicit whenever the target is linux/ARM or android/ARM.
This does not affect iOS where Apple provides its own linker.

In order to achieve this, we need to add `-fuse-ld=gold` to
the SettingsCCompilerLinkFlags setting and set
SettingsLdCommand to `ld.gold` (or `${target}-ld.gold` when
cross-compiling). In addition, simplifying the use of
`$(CONF_GCC_LINKER_OPTS_STAGEn)`.

This patch was tested by ensuring that the following worked
as expected:

  * Native builds on linux/x86_64 (nothing changed).
  * Native builds on linux/arm (and uses the gold linker).
  * Linux to linux/arm cross compiles (and uses the cross
    gold linker).

Contributions by Ben Gamari, Joachim Breitner and Reid Barton.

Reviewers: nomeata, bgamari, austin, rwbarton

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D715

GHC Trac Issues: #8976 #9873

1 files changed, 12 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index c64af90b62..e7d467f470 100644
--- a/configure.ac
+++ b/configure.ac
@@ -438,7 +438,18 @@ AC_SUBST([HaskellCPPArgs])
 dnl ** Which ld to use?
 dnl --------------------------------------------------------------
 FP_ARG_WITH_PATH_GNU_PROG([LD], [ld], [ld])
-LdCmd="$LD"
+case $target in
+arm*linux*)
+	# Arm requires use of the binutils ld.gold linker.
+	# This case should catch at least arm-unknown-linux-gnueabihf and
+	# arm-linux-androideabi.
+	FP_ARG_WITH_PATH_GNU_PROG([LD_GOLD], [ld.gold], [ld.gold])
+	LdCmd="$LD_GOLD"
+	;;
+*)
+	LdCmd="$LD"
+	;;
+esac
 AC_SUBST([LdCmd])
 
 dnl ** Which nm to use?