sys-power/iasl: Respect prefix

Thanks-to: Pengcheng Xu <i@jsteward.moe>
Closes: https://bugs.gentoo.org/642402
Package-Manager: Portage-2.3.79, Repoman-2.3.18
Signed-off-by: Lars Wendler <polynomial-c@gentoo.org>

sys-power/iasl/iasl-20190703.ebuild

@@ -44,7 +44,8 @@ src_prepare() {
 
 	find "${S}" -type f -name 'Makefile*' -print0 | \
 		xargs -0 -I '{}' \
-		sed -r -e 's:-\<Werror\>::g' -i '{}' \
+		sed -r -e 's:-\<Werror\>::g' -e "s:/usr:${EPREFIX}/usr:g" \
+		-i '{}' \
 		|| die
 
 	# BITS is tied to ARCH - please set appropriately if you add new keywords