To reproduce:
cd depends
make
cd ..
./configure --prefix=`pwd`/depends/x86_64-pc-linux-gnu
Problem:
checking for static Qt plugins: -lqminimal... no
configure: WARNING: Could not resolve: -lqminimal; bitcoin-qt frontend will not be built
checking for static Qt plugins: -lqxcb -lxcb-static... no
checking whether to build Bitcoin Core GUI... no (Qt5)
The actual problem is a linking issue when running the configuration check. From config.log:
/usr/bin/ld: /usr/lib/gcc/x86_64-pc-linux-gnu/8.2.1/../../../../lib/libharfbuzz.so: undefined reference to `FT_Done_MM_Var'
(Full snippet of relevant section in config.log)
I run Arch Linux, which currently uses harfbuzz 1.9.0. Downgrading harfbuzz to to 1.7.4 makes configure happy again (1.7.5 is the first version that fails) but that defeats the purpose of the depends build. Our depends system includes freetype 2.7.1 which however requires a specific version (range) of harfbuzz.
It seems that one naive way to resolve that issue is to include harfbuzz in depends but actually I don't know about all the magic and trade-offs going on the build system.
This may be related to #13001.