pkg-config file targets variable contains bogus backslashes
From /usr/lib64/pkgconfig/gtk4.pc from gtk4-4.4.1-1.fc35.x86_64 (but the same happens on master):
targets=broadway\ wayland\ x11
Note the extraneous backslashes after each except the last target's name.
This makes consuming this variable in a meson build rule more difficult, and wasn't the case for gtk3.