--- a/mozilla-firefox.SlackBuild	2021-08-24 21:29:28.183004321 +0300
+++ b/mozilla-firefox.SlackBuild	2021-09-08 20:15:56.607588628 +0300
@@ -42,6 +42,9 @@
 # "UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 36: ordinal not in range(128)"
 LANG=C
 
+# LTO needs more open files
+ulimit -n 4096
+
 # Add a shell script to start the firefox binary with MOZ_ALLOW_DOWNGRADE=1
 # to avoid backing up (and disabling) the user profile if a browser downgrade
 # is detected. We made it fine for years without this feature, and all the
@@ -152,6 +155,12 @@
 elif [ "$ARCH" = "armel" ]; then
   SLKCFLAGS="-g0 -march=armv4t"
   LIBDIRSUFFIX=""
+elif [ "$ARCH" = "aarch64" ]; then
+  SLKCFLAGS="-O2 -g0 -fPIC"
+  LIBDIRSUFFIX="64"
+elif [ "$ARCH" = "riscv64" ]; then
+  SLKCFLAGS="-O2 -g0 -fPIC"
+  LIBDIRSUFFIX="64"
 else
   SLKCFLAGS="-g0"
   LIBDIRSUFFIX=""
@@ -228,8 +237,16 @@
   \( -perm 666 -o -perm 664 -o -perm 600 -o -perm 444 -o -perm 440 -o -perm 400 \) \
   -exec chmod 644 {} \+
 
+xzcat $CWD/build-arm-libopus.patch.xz | patch -p1 --verbose || exit 1
+
 # Our building options, in a configure-like display ;)
 OPTIONS="\
+  --host=$ARCH-slackware-linux \
+  --target=$ARCH-slackware-linux \
+  --disable-av1 \
+  --disable-jemalloc \
+  --disable-webrtc \
+  \
   --enable-official-branding \
   --prefix=/usr \
   --libdir=/usr/lib${LIBDIRSUFFIX} \
@@ -242,7 +259,6 @@
   --enable-application=browser \
   --enable-default-toolkit=cairo-gtk3-wayland \
   --enable-linker=$LINKER \
-  --enable-optimize \
   $GOOGLE_API_KEY \
   --disable-strip \
   --disable-install-strip \
@@ -252,7 +268,6 @@
   --disable-crashreporter \
   --disable-debug-symbols \
   --disable-debug \
-  --disable-elf-hack \
   --disable-updater"
 # Complains about missing APNG support in Slackware's libpng:
 # --with-system-png \
@@ -312,6 +327,12 @@
 # Add the $OPTIONS above to .mozconfig:
 for option in $OPTIONS; do echo "ac_add_options $option" >> .mozconfig; done
 
+# ARM: see https://bugzilla.redhat.com/show_bug.cgi?id=1426850
+# This isn't added using $SLKCONFARGS because it doesn't cater for things with spaces in:
+# unless I edit the for loop above to use IFS with some other variable.
+# this is easier right now ;-)
+echo 'ac_add_options --enable-optimize="-g0 -O2"' >> .mozconfig
+
 # https://developer.mozilla.org/en-US/docs/Building_with_Profile-Guided_Optimization
 # Thanks to ArchLinux and Gentoo for the additional hints.
 if [ "$PGO" = "yes" ]; then