net-libs/libtirpc: Apply Flatcar modifications

Update keywords to stable amd64 and arm64.

Based on commit a729ef7.

sdk_container/src/third_party/coreos-overlay/net-libs/libtirpc/README.md

@@ -0,0 +1,7 @@
+This is a fork of gentoo package. We have it on overlay because:
+
+- We change the NETCONFIG macro value from `"/etc/netconfig"` to
+  `"/usr/share/tirpc/netconfig"`.
+
+- We update the installation of the netconfig accordingly to the
+  previous point.

sdk_container/src/third_party/coreos-overlay/net-libs/libtirpc/libtirpc-1.3.4.ebuild

@@ -14,7 +14,7 @@ SRC_URI="
 
 LICENSE="BSD BSD-2 BSD-4 LGPL-2.1+"
 SLOT="0/3" # subslot matches SONAME major
-KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux"
+KEYWORDS="~alpha amd64 ~arm arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux"
 IUSE="kerberos static-libs"
 
 RDEPEND="kerberos? ( >=virtual/krb5-0-r1[${MULTILIB_USEDEP}] )"
@@ -31,6 +31,10 @@ src_prepare() {
 	cp -ra "${WORKDIR}"/tirpc "${S}"/ || die
 
 	default
+
+	# Flatcar: Set netconfig path to /usr so NFS works in
+	# PXE/ISO-booted systems.
+	sed -i -e "s,/etc,/usr/share/tirpc," "${S}/tirpc/netconfig.h" || die
 }
 
 multilib_src_configure() {
@@ -59,7 +63,7 @@ multilib_src_install() {
 multilib_src_install_all() {
 	einstalldocs
 
-	insinto /etc
+	insinto /usr/share/tirpc
 	doins doc/netconfig
 
 	insinto /usr/include/tirpc