[commit: ghc] master: Compile with `--via-asm` when cross compiling. (5f6fcf7)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/5f6fcf7808b16d066ad0fb2068225b3f2e8363f7/ghc

>---------------------------------------------------------------

commit 5f6fcf7808b16d066ad0fb2068225b3f2e8363f7
Author: Moritz Angermann <moritz.angermann at gmail.com>
Date:   Fri Mar 2 16:16:52 2018 -0500

    Compile with `--via-asm` when cross compiling.
    
    This bumps `hsc2hs` and adds the new `--via-asm` flag,
    which allows to successfully cross compile the win32
    lirbary.
    
    - Compile with `--via-asm` when cross compiling. This requires
    haskell/hsc2hs#5 (https://github.com/haskell/hsc2hs/pull/5)
    
    Test Plan: ./validate
    
    Reviewers: bgamari
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, thomie, carter
    
    Differential Revision: https://phabricator.haskell.org/D4439


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5f6fcf7808b16d066ad0fb2068225b3f2e8363f7
 mk/config.mk.in | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mk/config.mk.in b/mk/config.mk.in
index e5ec04a..26b07f3 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -649,8 +649,12 @@ $(eval $(call set_stage_HSC2HS_OPTS,0))
 $(eval $(call set_stage_HSC2HS_OPTS,1))
 $(eval $(call set_stage_HSC2HS_OPTS,2))
 ifeq "$(CrossCompiling)" "YES"
-SRC_HSC2HS_OPTS_STAGE1 += --cross-compile
-SRC_HSC2HS_OPTS_STAGE2 += --cross-compile
+# We'll assume we compile with gcc or clang, and both support `-S` and can as such use the
+# --via-asm pass, which should be faster and is required for cross compiling to windows, as
+# the c compiler complains about non-constant expressions even though they are constant and
+# end up as constants in the assembly.
+SRC_HSC2HS_OPTS_STAGE1 += --cross-compile --via-asm
+SRC_HSC2HS_OPTS_STAGE2 += --cross-compile --via-asm
 endif
 SRC_HSC2HS_OPTS_STAGE0 += --cflag=-D$(HostArch_CPP)_HOST_ARCH --cflag=-D$(HostOS_CPP)_HOST_OS
 SRC_HSC2HS_OPTS_STAGE1 += --cflag=-D$(TargetArch_CPP)_HOST_ARCH --cflag=-D$(TargetOS_CPP)_HOST_OS