diff --git a/m4/guestfs_c.m4 b/m4/guestfs_c.m4
index b3177a26a..002c32f95 100644
--- a/m4/guestfs_c.m4
+++ b/m4/guestfs_c.m4
@@ -54,6 +54,7 @@ nw="$nw -Wunsafe-loop-optimizations" # just a warning that an optimization
                                      # was not possible, safe to ignore
 nw="$nw -Wstack-protector"           # Useless warning when stack protector
                                      # cannot being used in a function.
+nw="$nw -Wcast-align"                # Useless warning on arm >= 7, intel
 dnl things I might fix soon:
 nw="$nw -Wpacked"                    # Allow attribute((packed)) on structs
 nw="$nw -Wlong-long"                 # Allow long long since it's required