From 35f59d8ec0025647f75563c0bedecfc8e082a971 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Sat, 20 Jan 2024 09:35:50 +0000
Subject: build system: make compiler names configurable

The top-level Makefile hardcoded the host and cross compiler name
to "gcc".  Make it possible to set different values either on the
command line (make CROSS_COMPILER=clang) or in the configuration
file.
---
 Makefile | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

(limited to 'Makefile')

diff --git a/Makefile b/Makefile
index f1d6b20b4..51f460583 100644
--- a/Makefile
+++ b/Makefile
@@ -196,6 +196,28 @@ ARCH ?= $(SUBARCH)
 # Architecture as present in compile.h
 UTS_MACHINE := $(ARCH)
 
+HOST_COMPILER ?=
+ifeq ($(HOST_COMPILER),)
+HOST_COMPILER := $(shell grep ^CONFIG_HOST_COMPILER= .config 2>/dev/null)
+HOST_COMPILER := $(subst CONFIG_HOST_COMPILER=,,$(HOST_COMPILER))
+HOST_COMPILER := $(subst ",,$(HOST_COMPILER))
+#")
+endif
+ifeq ($(HOST_COMPILER),)
+HOST_COMPILER := gcc
+endif
+
+CROSS_COMPILER ?=
+ifeq ($(CROSS_COMPILER),)
+CROSS_COMPILER := $(shell grep ^CONFIG_CROSS_COMPILER= .config 2>/dev/null)
+CROSS_COMPILER := $(subst CONFIG_CROSS_COMPILER=,,$(CROSS_COMPILER))
+CROSS_COMPILER := $(subst ",,$(CROSS_COMPILER))
+#")
+endif
+ifeq ($(CROSS_COMPILER),)
+CROSS_COMPILER := gcc
+endif
+
 # SHELL used by kbuild
 CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
 	  else if [ -x /bin/bash ]; then echo /bin/bash; \
@@ -275,7 +297,7 @@ export quiet Q KBUILD_VERBOSE
 # Look for make include files relative to root of kernel src
 MAKEFLAGS += --include-dir=$(srctree)
 
-HOSTCC  	= gcc
+HOSTCC  	= $(HOST_COMPILER)
 HOSTCXX  	= g++
 HOSTCFLAGS	:=
 HOSTCXXFLAGS	:=
@@ -293,7 +315,7 @@ MAKEFLAGS += -rR
 # Make variables (CC, etc...)
 
 AS		= $(CROSS_COMPILE)as
-CC		= $(CROSS_COMPILE)gcc
+CC		= $(CROSS_COMPILE)$(CROSS_COMPILER)
 LD		= $(CC) -nostdlib
 CPP		= $(CC) -E
 AR		= $(CROSS_COMPILE)ar
-- 
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