From de8c92a5967f64acfcf4bc93b2eb789d81b4c0a8 Mon Sep 17 00:00:00 2001
From: Adam Retter <adam.retter@googlemail.com>
Date: Tue, 14 Jul 2020 16:00:05 -0700
Subject: [PATCH] Only check for python location once (#7123)

Summary:
This fixes an issue introduced in 0c56fc4 whereby the location of Python is evaluated many times and leads to excessive logging of unknown python locations of CentOS 6.

The location is now only checked once.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7123

Reviewed By: zhichao-cao

Differential Revision: D22532274

Pulled By: ajkr

fbshipit-source-id: cade71b4b46e9a23d63ecb4dd36a4ac8ae217970
---
 Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 6501ea759..472b673f5 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,9 @@
 BASH_EXISTS := $(shell which bash)
 SHELL := $(shell which bash)
 # Default to python3. Some distros like CentOS 8 do not have `python`.
-PYTHON?=$(shell which python3 || which python || echo python3)
+ifeq ($(origin PYTHON), undefined)
+	PYTHON := $(shell which python3 || which python || echo python3)
+endif
 export PYTHON
 
 CLEAN_FILES = # deliberately empty, so we can append below.