[XEN PATCH] build: Replace `which` with `command -v`

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

The `which` command is not standard, may not exist on the build host,
or may not behave as expected. It is recommanded to use `command -v`
to find out if a command exist and have it's path, and it's part of a
POSIX shell standard.

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 xen/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/Makefile b/xen/Makefile
index 21832d6402..767e47d6c7 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -25,8 +25,8 @@ export XEN_BUILD_HOST := $(shell hostname)
 endif
 
 # Best effort attempt to find a python interpreter, defaulting to Python 3 if
-# available.  Fall back to just `python` if `which` is nowhere to be found.
-PYTHON_INTERPRETER     := $(word 1,$(shell which python3 python python2 
2>/dev/null) python)
+# available.  Fall back to just `python`.
+PYTHON_INTERPRETER     := $(word 1,$(shell command -v python3 || command -v 
python || command -v python2) python)
 export PYTHON          ?= $(PYTHON_INTERPRETER)
 
 export CHECKPOLICY     ?= checkpolicy
-- 
Anthony PERARD