depends: use MacOS friendly sed syntax in qt.mk #13750

I just got this error on master:

make clean-all
make -j5
[...]
/bitcoin/depends/sources/qttools-opensource-src-5.9.6.tar.xz: OK
Preprocessing qt...
sed: 1: "qtbase/mkspecs/bitcoin- ...": extra characters at the end of q command
make: *** /bitcoin/depends/work/build/x86_64-apple-darwin17.7.0/qt/5.9.6-b48df1b490b/.stamp_preprocessed] Error 1

With all these MacOS specific exceptions popping up recently, I almost wonder if it would not be more beneficial to "expect" (or even enforce) brew GNU versions of tools to be installed rather than the archaic pseudo-BSD MacOS versions?

This line goes away again in #13696 by the way.

archaic pseudo-BSD MacOS versions

Maybe, but apparently OpenBSB often encounters the same issues (cc @laanwj), so macOS devs help catch problems there this way :-)

This is not the first time sed has been used in depends, there are already multiple uses in the same file that all work fine on macOS. Something like:

sed -i.old "s/arm-linux-gnueabi-/$(host)-/g" qtbase/mkspecs/bitcoin-linux-g++/qmake.conf && \

should work fine?

@fanquake yes, my comment stems from knowing that (in general) there are some differences between MacOS sed and GNU sed...irregardless of wither those differences have ever surfaced here.

@fanquake I'll try sed -i.old for consistency.

@Fuzzbawls Sure, sorry if I sounded dismissive. There definitely are some differences, i.e something like #13514 which I stumbled on when playing around with iOS depends builds.

@fanquake hey no worries mate! I myself don't even know all the (seemingly stupid) differences between MacOS tools and GNU (or even more recent BSD).

I just know there are differences...and those differences may ore may not ever apply here...and if they do...lets make sure they are exclusive to MacOS and exclude them for being archaic (require brew GNU equivilent in this case) rather than cater to such exclusions.

utACK 12c93cb

utACK 12c93cb85b6cb075d22323ff02acebbe05e42375