dev-libs/npth: Sync with Gentoo

It's from Gentoo commit 3ff614480f07749fd8f7be78f7f8bd75c02c2a53.

sdk_container/src/third_party/portage-stable/dev-libs/npth/npth-1.6-r2.ebuild

@@ -0,0 +1,34 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit autotools flag-o-matic
+
+DESCRIPTION="New GNU Portable Threads Library"
+HOMEPAGE="https://git.gnupg.org/cgi-bin/gitweb.cgi?p=npth.git"
+SRC_URI="mirror://gnupg/${PN}/${P}.tar.bz2"
+
+LICENSE="LGPL-2.1+"
+SLOT="0"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos ~x64-solaris"
+IUSE="test"
+RESTRICT="!test? ( test )"
+
+src_prepare() {
+	default
+	eautoreconf
+}
+
+src_configure() {
+	append-ldflags $(test-flags-CCLD -Wl,--undefined-version)
+
+	econf $(use_enable test tests)
+}
+
+src_install() {
+	default
+
+	# no static archives
+	find "${ED}" -name '*.la' -delete || die
+}