Get:1 http://us.archive.ubuntu.com/ubuntu cosmic-updates/main firefox 64.0+build3-0ubuntu0.18.10.1 (diff) [250 kB]
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sed: can't read firefox_64.0.dsc: No such file or directory
sed: can't read firefox_64.0.dsc: No such file or directory
I did make progress by hacking up the script a bit but am so far down the rabbit hole at this point that I figured I'd just post the original error. Even with my changes, I'm still unable to compile anyway.
sudo apt-get build-dep firefox
apt-get source firefox
cd firefox-*
dpkg-buildpackage -b -us -uc
but after about 30 minutes...
*** KEEP ALIVE MARKER ***
Total duration: 0:34:00.894319
34:38.55 {standard input}: Assembler messages:
34:38.56 {standard input}:337397: Warning: end of file not at end of a line; newline inserted
34:38.56 {standard input}:338697: Error: unknown pseudo-op: `.lbb39262'