ARC: build: Don't set CROSS_COMPILE in arch's Makefile

There's not much sense in doing that because if user or
his build-system didn't set CROSS_COMPILE we still may
very well make incorrect guess.

But as it turned out setting CROSS_COMPILE is not as harmless
as one may think: with recent changes that implemented automatic
discovery of __host__ gcc features unconditional setup of
CROSS_COMPILE leads to failures on execution of "make xxx_defconfig"
with absent cross-compiler, for more info see [1].

Set CROSS_COMPILE as well gets in the way if we want only to build
.dtb's (again with absent cross-compiler which is not really needed
for building .dtb's), see [2].

Note, we had to change LIBGCC assignment type from ":=" to "="
so that is is resolved on its usage, otherwise if it is resolved
at declaration time with missing CROSS_COMPILE we're getting this
error message from host GCC:

| gcc: error: unrecognized command line option -mmedium-calls
| gcc: error: unrecognized command line option -mno-sdata

[1] http://lists.infradead.org/pipermail/linux-snps-arc/2018-September/004308.html
[2] http://lists.infradead.org/pipermail/linux-snps-arc/2018-September/004320.html

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 0dbce02..644815c 100644 (file)
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -6,14 +6,6 @@
 # published by the Free Software Foundation.
 #
 
-ifeq ($(CROSS_COMPILE),)
-ifndef CONFIG_CPU_BIG_ENDIAN
-CROSS_COMPILE := arc-linux-
-else
-CROSS_COMPILE := arceb-linux-
-endif
-endif
-
 KBUILD_DEFCONFIG := nsim_700_defconfig
 
 cflags-y       += -fno-common -pipe -fno-builtin -mmedium-calls -D__linux__
@@ -65,7 +57,7 @@ cflags-$(disable_small_data)          += -mno-sdata -fcall-used-gp
 cflags-$(CONFIG_CPU_BIG_ENDIAN)                += -mbig-endian
 ldflags-$(CONFIG_CPU_BIG_ENDIAN)       += -EB
 
-LIBGCC := $(shell $(CC) $(cflags-y) --print-libgcc-file-name)
+LIBGCC = $(shell $(CC) $(cflags-y) --print-libgcc-file-name)
 
 # Modules with short calls might break for calls into builtin-kernel
 KBUILD_CFLAGS_MODULE   += -mlong-calls -mno-millicode