I've just had a try at building palemoon without the instruction set extensions.
unsure I got all the flags. they seem to be scattered all over the place.
unsure how to enable the mail client...
I did however end up with a working browser that'll run on a box without sse2.
In case someone else is having similar troubles here's a patch.
the patch is against their
> Pale-Moon-29.2.1_Release.tar.gz
and
> RELBASE_20210608.tar.gz
do roughly the following:
tar -xf ./Pale-Moon-29.2.1_Release.tar.gz
cd ./pale-moon
tar -xf ../RELBASE_20210608.tar.gz
rmdir ./platform
mv ./uxp ./platform
patch -p2 <../crapcompilerflags.patch
./mach build
./mach package
cd /usr/lib
(as root)tar -xf <wherever>/pale-moon/obj-i686-pc-linux-gnu/dist/palemoon-29.2.1.linux-i686-gtk2.tar.xz
cd palemoon
(as user) ./palemoon-bin
note the errors and hunt for the remaining .so files in the obj directory.
copy them here then run ldconfig as root
and retry ./palemoon-bin
until the crap works
crapcompilerflags.patch: <
https://pastebin.com/raw/qMD2hmnH>