sys-devel/compat-headers: new package

This is pretty much an exact duplicate of Alpine's bsd-compat-headers

sys-devel/compat-headers/Manifest

+DIST cdefs.h 539 SHA256 30bb6d7e0e0b61fcd95d830c376c829a614bce4683c1b97e06c201ec2c6e839a SHA512 8c3fddd73b696a38e633953715c79c47703739be27ee085fc6c960a57b6746ca05bf6406f7e6126cc1a13204254fd5830afb566624e1f298f4d6b58216013c28 WHIRLPOOL 0337d2980a3873586568e6c99f8ef468a8fa0266de9b730750f96a5197ad01e4dcaf07518fba8704970c23c1de0c79b51551a1be8528082af878e0b3f622e7da
+DIST queue.h 30107 SHA256 3659cd137c320991a78413dd370a92fd18e0a8bc36d017d554f08677a37d7d5a SHA512 19cec4d39310285eb49ad1beae86884080e0152f9477757513050211b31f95ee7283a64ae95939683df09231cfb021ace816b26981ad05f4fff0a39519f935fe WHIRLPOOL 585fa98449fbf44fa4c4a2db770f42acc343a3d4150b6253d839090c6061cfc69b6b694a145399a524e83f0eaded6f0c0d32b2ae15919acff370190586b83c59
+DIST tree.h 25768 SHA256 e1e498a79bf160a5766fa560f2b07b206fe89fe21a62600c77d72e00a6992f92 SHA512 07cb70f2f0ddb31e23dd913c6f561fc9885667c5803fdf3a559676c99d08834b4104589bacb5d17b4a0b379c68c81a1cf3173832b3da33a7b936fa7b93706844 WHIRLPOOL 65e548a1113d25e45bac224d5d26d40bdb031148b7442119ef6537ecf84fc9b3b05723e569adb2063ca7c6985a76f37e6be4a13d51ec65803bb77508884b74a9

sys-devel/compat-headers/compat-headers-1.0.ebuild

+# Copyright 2015-2016 Adélie Linux Team
+# Distributed under the terms of the NCSA License
+
+EAPI=6
+
+DESCRIPTION="Development headers for compatibility with BSD and glibc"
+HOMEPAGE="http://alpinelinux.org/"
+SRC_URI="http://git.alpinelinux.org/cgit/aports/plain/main/libc-dev/sys-cdefs.h?id=e3725c0af137717d6883265a92db3838900b5cee -> cdefs.h
+	http://git.alpinelinux.org/cgit/aports/plain/main/libc-dev/sys-queue.h?id=e3725c0af137717d6883265a92db3838900b5cee -> queue.h
+	http://git.alpinelinux.org/cgit/aports/plain/main/libc-dev/sys-tree.h?id=e3725c0af137717d6883265a92db3838900b5cee -> tree.h"
+
+LICENSE="BSD-2 BSD-3 GPL2"
+SLOT="0"
+KEYWORDS="arm mips ppc ppc64 x86 x86_64"
+IUSE=""
+
+DEPEND="!sys-libs/glibc"
+RDEPEND="${DEPEND}"
+
+src_unpack () {
+	mkdir -p "${S}"
+	for header in cdefs.h queue.h tree.h; do
+		cp "${DISTDIR}/${header}" "${S}"
+	done
+}
+
+src_install () {
+	insinto /usr/include/sys
+	doins cdefs.h queue.h tree.h
+}