#!/bin/bash

function grepdep {
    while read pkgbuild; do
	unset depends makedepends
	source $pkgbuild
	for depfield in "makedepends[@]" "depends[@]"; do 
	    for depend in ${!depfield}; do
		[[ ${depend%%[<>=]*} = "$1" ]] && echo $pkgbuild -- $depfield $depend
	    done
	done
    done
}

if [[ "" = "$1" ]]; then 
    echo "Specify a package!" >&2 
    exit 1
fi

find . -name PKGBUILD|grepdep $1