Partial undo last commit; there are still issues with pyside

PKGBUILD

@@ -30,6 +30,10 @@ pkgver() {
 build() {
     cd "${srcdir}/${pkgname}"
 
+    # we need to manually set all PYSIDE_* paths as autodetection is broken:
+    # https://github.com/FreeCAD/FreeCAD/pull/2020
+    PYVER="$(/usr/bin/python3 -c 'import sys; print("{}.{}".format(sys.version_info.major,sys.version_info.minor))')"
+
     cmake \
         -DCMAKE_BUILD_TYPE=Release \
         -DCMAKE_INSTALL_PREFIX="/usr/lib/freecad" \
@@ -39,6 +43,10 @@ build() {
         -DBUILD_QT5=ON \
         -DPYTHON_EXECUTABLE=/usr/bin/python3 \
         -DOPENMPI_INCLUDE_DIRS=/usr/include \
+        -DPYSIDE_INCLUDE_DIR="/usr/include/PySide2" \
+        -DPYSIDE_LIBRARY="/usr/lib/libpyside2.cpython-${PYVER//.}m-${CARCH}-linux-gnu.so" \
+        -DPYSIDE_PYTHONPATH="/usr/lib/python${PYVER}/site-packages/PySide2" \
+        -DPYSIDE_TYPESYSTEMS="/usr/share/PySide2/typesystems" \
         .
     make
 }