Fake makepkg enough to build and install android-protobuf from PKGBUILD

fakepkg.bash

#!/bin/bash
# Fake makepkg enough to build and install android-protobuf PKGBUILD

# Go into sanity mode
set -eEuo pipefail

# Heuristics, do your job if not true.
PROTOC="$(which protoc)"
MAKEFLAGS="$@"

# Setup common makepkg variables
startdir="$PWD/build"
srcdir="$startdir"
pkgdir="$PWD/install"

# msg is used by some PKGBUILDs
msg() { printf -- "==> $1\n" "${@:2}" 1>&2; }

# Source the recipe
source ./PKGBUILD

# Prepare the work env
mkdir -p "$startdir"
cd "$startdir"

# Fetch the sources by assuming everything is a
# curl friendly url and tar -xf extractable
for s in "${source[@]}"; do
    prefix="${s%::*}"
    [[ "$prefix" == "$s" ]] && prefix=
    url="${s##*::}"
    fname="${prefix:-${url##*/}}"
    curl -L "$url" -o "$fname"

    ext="${fname##*.}"
    case "$ext" in
    tar)
        tar -xf "$fname"
        ;;
    zip)
        unzip -qf "$fname"
        ;;
    esac
done

# Build the thing
cd "$startdir"; prepare
cd "$startdir"; build

# Export to fakeroot
export ANDROID_NDK PROTOC MAKEFLAGS startdir srcdir pkgdir
export -f msg

# Package the thing inside fakeroot
cd "$startdir"; fakeroot -- bash << EOF
set -eEuo pipefail
source ../PKGBUILD
package
exit \$?
EOF

# Install to /usr/local and remove temporary $pkgdir
sudo cp -R "$pkgdir/"* /usr/local/
rm -r "$pkgdir"