gnu: python-cu2qu: Fix tests.

* gnu/packages/fontutils.scm (python-cu2qu): Fix tests.
[build-system]: Switch to pyproject-build-system.
[arguments]{test-flags}: Ignore failing test (most likely due to
lagging behing python-fonttools package).
[native-inputs]: Add python-setuptools, python-wheel.
* gnu/packages/python-xyz.scm (python-fonttools-minimal): Add comment.

Signed-off-by: Sharlatan Hellseher <sharlatanus@gmail.com>

gnu/packages/fontutils.scm

@@ -505,14 +505,19 @@ subroutinizer for fontTools.")
        (uri (pypi-uri "cu2qu" version ".zip"))
        (sha256
         (base32 "1x762r7bf39g6aivfvrmq00h6f07abvs9x1xm0fz8l81vq8jz64c"))))
-    (build-system python-build-system)
+    (build-system pyproject-build-system)
+    (arguments
+     ;; XXX: Try to remove it when updating python-fonttools.
+     (list #:test-flags #~(list "-k" "not test_ignore_single_points")))
     (propagated-inputs (list python-fonttools))
     (native-inputs
      (list python-cython
            python-defcon
            python-pytest
            python-pytest-runner
+           python-setuptools
            python-setuptools-scm
+           python-wheel
            unzip))
     (home-page "https://github.com/googlefonts/cu2qu")
     (synopsis "Cubic-to-quadratic bezier curve conversion")

gnu/packages/python-xyz.scm

@@ -17273,6 +17273,7 @@ number of lines in the contained files easily.")
     (license license:expat)))
 
 ;;; Tests are left out in the main package to avoid cycles.
+;; XXX: When updating, solve comment in python-cu2qu.
 (define-public python-fonttools-minimal
   (hidden-package
    (package