use glibc 2.22 to work around assembler error
diff --git a/initramfs-build.sh b/initramfs-build.sh
index 3c08807..65abf39 100755
--- a/initramfs-build.sh
+++ b/initramfs-build.sh
@@ -73,6 +73,7 @@
 BR2_TARGET_ROOTFS_CPIO=y
 BR2_TARGET_ROOTFS_CPIO_XZ=y
 BR2_TARGET_GENERIC_GETTY_PORT="hvc0"
+BR2_GLIBC_VERSION_2_22=y
 EOF_BUILDROOT
 
 # Build buildroot