build_mesa_i965.sh

#!/bin/bash
PS1="[isolated] $PS1"

export VK_ICD_FILENAMES=$HOME/igalia/install/share/vulkan/icd.d/intel_icd.x86_64.json
#export VK_ICD_FILENAMES=$HOME/igalia/install/share/vulkan/icd.d/radeon_icd.x86_64.json

export PATH=$PATH:$HOME/igalia/install/bin
export LD_LIBRARY_PATH=$HOME/igalia/install/lib
export LD_RUN_PATH=$HOME/igalia/install/lib
export XDG_DATA_DIRS=$XDG_DATA_DIRS:$HOME/igalia/install/share

export LIBGL_DRIVERS_PATH=~/igalia/install/lib/x86_64-linux-gnu/dri/
export MESA_DEBUG=1

#intel specific
#iris:
#export MESA_LOADER_DRIVER_OVERRIDE=iris

git clone https://gitlab.freedesktop.org/mesa/mesa.git
cd mesa
mkdir -p build
#iris:
#meson ~/igalia/code/mesa/build -Ddri-drivers=swrast,i965 -Dgallium-drivers=iris -Dbuildtype=debug -Dvulkan-drivers=intel
#i965:
meson ~/igalia/code/mesa/build -Dtools=intel -Ddri-drivers=i965 -Dprefer-iris=false -Dbuildtype=debug -Dvulkan-drivers=intel
meson configure --prefix=$HOME/igalia/install/ ~/igalia/code/mesa/build
ninja -C ~/igalia/code/mesa/build/ install

ln -s ~/igalia/code/mesa/build/compile_commands.json .

-Dprefer-iris=false and -Ddri-drivers=i965 do the trick