From b1876222335df6581777baadc68fb5b17e5fe656 Mon Sep 17 00:00:00 2001
From: Disservin <disservin.social@gmail.com>
Date: Sun, 22 Oct 2023 16:43:33 +0200
Subject: [PATCH] use expanded variables for shell commands

Performance improvement for the shell commands in the Makefile.
By using expanded variables, the shell commands are only
evaluated once, instead of every time they are used.

closes https://github.com/official-stockfish/Stockfish/pull/4838

No functional change
---
 src/Makefile | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 7b7ee41b..76ef6fde 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -20,9 +20,9 @@
 ### ==========================================================================
 
 ### Establish the operating system name
-KERNEL = $(shell uname -s)
+KERNEL := $(shell uname -s)
 ifeq ($(KERNEL),Linux)
-	OS = $(shell uname -o)
+	OS := $(shell uname -o)
 endif
 
 ### Target Windows OS
@@ -33,7 +33,7 @@ ifeq ($(OS),Windows_NT)
 else ifeq ($(COMP),mingw)
 	target_windows = yes
 	ifeq ($(WINE_PATH),)
-		WINE_PATH = $(shell which wine)
+		WINE_PATH := $(shell which wine)
 	endif
 endif
 
@@ -116,7 +116,7 @@ ifeq ($(ARCH),)
 endif
 
 ifeq ($(ARCH), native)
-   override ARCH = $(shell $(SHELL) ../scripts/get_native_properties.sh | cut -d " " -f 1)
+   override ARCH := $(shell $(SHELL) ../scripts/get_native_properties.sh | cut -d " " -f 1)
 endif
 
 # explicitly check for the list of supported architectures (as listed with make help),
@@ -542,8 +542,8 @@ endif
 
 ### Sometimes gcc is really clang
 ifeq ($(COMP),gcc)
-	gccversion = $(shell $(CXX) --version 2>/dev/null)
-	gccisclang = $(findstring clang,$(gccversion))
+	gccversion := $(shell $(CXX) --version 2>/dev/null)
+	gccisclang := $(findstring clang,$(gccversion))
 	ifneq ($(gccisclang),)
 		profile_make = clang-profile-make
 		profile_use = clang-profile-use
@@ -601,7 +601,7 @@ ifeq ($(optimize),yes)
 	endif
 
 	ifeq ($(comp),clang)
-		clangmajorversion = $(shell $(CXX) -dumpversion 2>/dev/null | cut -f1 -d.)
+		clangmajorversion := $(shell $(CXX) -dumpversion 2>/dev/null | cut -f1 -d.)
 		ifeq ($(shell expr $(clangmajorversion) \< 16),1)
 			CXXFLAGS += -fexperimental-new-pass-manager
 		endif
@@ -717,13 +717,13 @@ ifeq ($(pext),yes)
 endif
 
 ### 3.8.1 Try to include git commit sha for versioning
-GIT_SHA = $(shell git rev-parse HEAD 2>/dev/null | cut -c 1-8)
+GIT_SHA := $(shell git rev-parse HEAD 2>/dev/null | cut -c 1-8)
 ifneq ($(GIT_SHA), )
 	CXXFLAGS += -DGIT_SHA=$(GIT_SHA)
 endif
 
 ### 3.8.2 Try to include git commit date for versioning
-GIT_DATE = $(shell git show -s --date=format:'%Y%m%d' --format=%cd HEAD 2>/dev/null)
+GIT_DATE := $(shell git show -s --date=format:'%Y%m%d' --format=%cd HEAD 2>/dev/null)
 ifneq ($(GIT_DATE), )
 	CXXFLAGS += -DGIT_DATE=$(GIT_DATE)
 endif
-- 
2.39.2