tools: Factor HOSTCC, HOSTLD, HOSTAR definitions

mainline inclusion
from mainline-5.11-rc1
commit c8a950d0
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c8a950d0d3b926a02c7b2e713850d38217cec3d1

-------------------------------------------------

Several Makefiles in tools/ need to define the host toolchain variables.
Move their definition to tools/scripts/Makefile.include
Signed-off-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/bpf/20201110164310.2600671-2-jean-philippe@linaro.org
(cherry picked from commit c8a950d0)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>

tools/scripts/Makefile.include

@@ -77,6 +77,16 @@ HOSTCC  ?= gcc
 HOSTLD  ?= ld
 endif
 
+ifneq ($(LLVM),)
+HOSTAR  ?= llvm-ar
+HOSTCC  ?= clang
+HOSTLD  ?= ld.lld
+else
+HOSTAR  ?= ar
+HOSTCC  ?= gcc
+HOSTLD  ?= ld
+endif
+
 ifeq ($(CC_NO_CLANG), 1)
 EXTRA_WARNINGS += -Wstrict-aliasing=3
 endif