32-bit ARM assembler is mostly for Android32 accel anyway.

It doesn't link properly on musl (TEXTRELs).

--- thunderbird-91.13.0/toolkit/moz.configure.old	2023-10-09 10:40:18.231733637 +0000
+++ thunderbird-91.13.0/toolkit/moz.configure	2023-10-10 02:22:34.743712070 +0000
@@ -1894,7 +1894,7 @@
                 flac_only = True
         elif target.cpu == "x86_64":
             flags = ["-D__x86_64__", "-DPIC", "-DELF", "-Pconfig_unix64.asm"]
-        elif target.cpu in ("x86", "arm", "aarch64"):
+        elif target.cpu in ("x86", "aarch64"):
             flac_only = True
         else:
             enable = False