Build with --enable-unaligned-private-values

This is what gjs upstream recommends to use:

"--enable-unaligned-private-values: This one is also strictly required,
to prevent data corruption issues with byte arrays."

See https://mail.gnome.org/archives/distributor-list/2020-February/msg00000.html

mozjs68.spec

@@ -20,7 +20,7 @@
 
 Name:           mozjs%{major}
 Version:        68.4.2
-Release:        2%{?dist}
+Release:        3%{?dist}
 Summary:        SpiderMonkey JavaScript library
 
 License:        MPLv2.0 and MPLv1.1 and BSD and GPLv2+ and GPLv3+ and LGPLv2+ and AFL and ASL 2.0
@@ -154,6 +154,7 @@ autoconf-2.13
   --disable-optimize \
   --enable-pie \
   --disable-jemalloc \
+  --enable-unaligned-private-values
 
 %if 0%{?big_endian}
 echo "Generate big endian version of config/external/icu/data/icud58l.dat"
@@ -249,6 +250,9 @@ PYTHONPATH=tests/lib %{__python3} jit-test/jit_test.py -s -t 1800 --no-progress
 %{_includedir}/mozjs-%{major}/
 
 %changelog
+* Mon Feb 03 2020 Kalev Lember <klember@redhat.com> - 68.4.2-3
+- Build with --enable-unaligned-private-values
+
 * Wed Jan 29 2020 Fedora Release Engineering <releng@fedoraproject.org> - 68.4.2-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_32_Mass_Rebuild