Add Gentoo Portage host configuration

bashrc

@@ -0,0 +1,18 @@
+
+# BEGIN managed Portage Btrfs snapshots
+# Portage invokes these phase hooks after package post-install and post-remove.
+# This is one snapshot per changed package, not one per emerge command.
+post_pkg_postinst() {
+    /usr/local/libexec/portage-btrfs-snapshot install "${CATEGORY:-unknown}" "${PF:-unknown}" "${ROOT:-/}" "${EROOT:-/}" || \
+        printf '!!! Btrfs snapshot failed after installing %s/%s.\n' "${CATEGORY:-unknown}" "${PF:-unknown}" >&2
+}
+
+post_pkg_postrm() {
+    /usr/local/libexec/portage-btrfs-snapshot remove "${CATEGORY:-unknown}" "${PF:-unknown}" "${ROOT:-/}" "${EROOT:-/}" || \
+        printf '!!! Btrfs snapshot failed after removing %s/%s.\n' "${CATEGORY:-unknown}" "${PF:-unknown}" >&2
+}
+# END managed Portage Btrfs snapshots
+
+if [ "${PN}" = "firefox" ]; then
+    export RUSTFLAGS="${RUSTFLAGS} -C target-feature=-crt-static"
+fi