###Download source
For Chaos Calmer 15.05
git clone git://git.openwrt.org/15.05/openwrt.git
For Barrier Breaker 14.07
git clone git://git.openwrt.org/14.07/openwrt.git
###Install Quilt quilt is the tools OpenWrt used to manage patches. You need to install it before you use patches. http://wiki.openwrt.org/doc/devel/patches
sudo apt-get install quilt
Configure quilt according to openwrt docs.
cat > ~/.quiltrc <<EOF
QUILT_DIFF_ARGS="--no-timestamps --no-index -p ab --color=auto"
QUILT_REFRESH_ARGS="--no-timestamps --no-index -p ab"
QUILT_PATCH_OPTS="--unified"
QUILT_DIFF_OPTS="-p"
EDITOR="nano"
EOF
###Apply patches
cd openwrt
mkdir patches
cp [gl-ar150.patch series] patches
quilt push -a