Add a CMakeLists.txt to initialize and drive the first build.

This keeps all the environment variables sane and allows for
out-of-this-tree builds.

Usage:
    cmake -B ../build -DINSTALL_ROOT=/local/mnt/new-toolchain_for_hexagon/install

cd to ../build and issue a, "make tools" command to build everything.

Signed-off-by: Sid Manning <sidneym@quicinc.com>

CMakeLists.txt

@@ -0,0 +1,59 @@
+cmake_minimum_required(VERSION 3.22)
+project(
+  "Hexagon open source toolchain"
+  DESCRIPTION "It is a sample toolchain to support Hexagon"
+  HOMEPAGE_URL "https://github.com/quic/toolchain_for_hexagon"
+  LANGUAGES NONE)
+
+
+# Set variables with CACHE option to allow command line override
+set(HOST_CLANG_VER 20 CACHE STRING "Host Clang version")
+set(ARTIFACT_TAG 20.0.0 CACHE STRING "Artifact tag")
+set(INSTALL_ROOT /tmp/$ENV{USER}/hexagon-qemu CACHE STRING "Install root")
+set(TOOLCHAIN_INSTALL ${INSTALL_ROOT}/clang+llvm-${ARTIFACT_TAG}-cross-hexagon-unknown-linux-musl)
+set(ROOT_INSTALL ${INSTALL_ROOT}/install_rootfs)
+set(ARTIFACT_BASE ${INSTALL_ROOT}/artifacts)
+
+set(TOOLCHAIN_INSTALL_REL ${TOOLCHAIN_INSTALL})
+set(TOOLCHAIN_BIN ${TOOLCHAIN_INSTALL}/x86_64-linux-gnu/bin)
+set(TOOLCHAIN_LIB ${TOOLCHAIN_INSTALL}/x86_64-linux-gnu/lib)
+set(HEX_SYSROOT ${TOOLCHAIN_INSTALL}/x86_64-linux-gnu/target/hexagon-unknown-linux-musl)
+set(HEX_TOOLS_TARGET_BASE ${HEX_SYSROOT}/usr)
+set(ROOT_INSTALL_REL ${ROOT_INSTALL})
+set(ROOTFS ${ROOT_INSTALL})
+set(RESULTS_DIR ${ARTIFACT_BASE}/${ARTIFACT_TAG})
+
+# Custom commands
+add_custom_target(setup
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${ARTIFACT_BASE}
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${RESULTS_DIR}
+    COMMAND ${CMAKE_COMMAND} -E echo_append ${CMAKE_CURRENT_SOURCE_DIR}
+    COMMAND ${CMAKE_COMMAND} -E echo_append ${TOOLCHAIN_INSTALL_REL}
+)
+
+add_custom_target(clone
+    DEPENDS setup
+    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/get-src-repos.sh ${CMAKE_CURRENT_SOURCE_DIR} ${TOOLCHAIN_INSTALL_REL}
+)
+
+add_custom_target(eld
+    DEPENDS clone
+    COMMAND ${CMAKE_COMMAND} -E chdir llvm-project git clone git@github.qualcomm.com:cgit/eld.git
+)
+
+#
+# NOTE:
+#   DEPENDS eld
+# Remove this when incrementally building
+# the scripts are very picky about running more than once.
+#
+add_custom_target(tools
+    DEPENDS eld
+    COMMAND
+    env TOOLCHAIN_INSTALL=${TOOLCHAIN_INSTALL}
+    env ROOT_INSTALL=${ROOT_INSTALL}
+    env ARTIFACT_BASE=${ARTIFACT_BASE}
+    env ARTIFACT_TAG=${ARTIFACT_TAG}
+    ${CMAKE_CURRENT_SOURCE_DIR}/build-toolchain.sh
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+)

build-toolchain.sh

@@ -131,7 +131,7 @@ build_clang_rt_builtins() {
 
 config_kernel() {
 	cd ${BASE}
-	mkdir obj_linux
+	mkdir -p obj_linux
 	cd linux
 	make O=../obj_linux ARCH=hexagon \
 		CROSS_COMPILE=hexagon-unknown-linux-musl- \
@@ -253,7 +253,7 @@ build_qemu() {
 	                  --enable-slirp \
 	                  --enable-plugins \
 	                  --disable-containers \
-	                  --python=$(which python3.8) \
+	                  --python=$(which python) \
 		--target-list=hexagon-softmmu,hexagon-linux-user --prefix=${TOOLCHAIN_INSTALL}/x86_64-linux-gnu \
 
 #	--cc=clang \
@@ -322,7 +322,7 @@ which clang
 clang --version
 ninja --version
 cmake --version
-python3.8 --version
+python --version
 
 build_llvm_clang
 

get-src-repos.sh

@@ -21,12 +21,14 @@ git clone -q --branch=hexagon https://github.com/quic/musl &
 git clone -q https://github.com/quic/hexagonMVM &
 git clone -q https://github.com/qemu/qemu &
 
+gitdirs="qemu llvm-test-suite musl linux busybox hexagonMVM llvm-project libc-test buildroot cpython"
+
 wait
 
 dump_checkout_info() {
 	out=${1}
 	mkdir -p ${out}
-	for d in ./*
+	for d in ${gitdirs}
 	do
 		if [[ -d ${d} ]]; then
 			proj=$(basename ${d})