...
Linking...
clang-9: error: unsupported option '--libs'
clang-9: error: unsupported option '--libs'
...
clang-9: error: no such file or directory: '`pkg-config'
clang-9: error: no such file or directory: 'freetype2`'
clang-9: error: no such file or directory: '`pkg-config'
clang-9: error: no such file or directory: 'x11`'
clang-9: error: no such file or directory: '`pkg-config'
clang-9: error: no such file or directory: 'fontconfig`'
...

./umk uppsrc ide CLANG -rbs ./theide