x11-themes/qtcurve-gtk2: Fix configure

Fix configure with KDE Frameworks 5.93.0
https://cgit.freebsd.org/ports/commit/?id=cbf73704b339d4c617d45b442a845c596b955c29

After changes to the CMake modules, it now expects to find qmake
and the Qt buildtools.

CMake Error at /usr/local/lib/cmake/Qt5Core/Qt5CoreConfig.cmake:14 (message):
  The imported target "Qt5::Core" references the file

     "/usr/local/lib/qt5/bin/qmake"

  but this file does not exist.  Possible reasons include:

  * The file was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and contained

     "/usr/local/lib/cmake/Qt5Core/Qt5CoreConfigExtras.cmake"

  but not all the files it references.

Call Stack (most recent call first):
  /usr/local/lib/cmake/Qt5Core/Qt5CoreConfigExtras.cmake:9 (_qt5_Core_check_file_exists)
  /usr/local/lib/cmake/Qt5Core/Qt5CoreConfig.cmake:232 (include)
  /usr/local/share/cmake/Modules/CMakeFindDependencyMacro.cmake:47 (find_package)
  /usr/local/lib/cmake/KF5I18n/KF5I18nConfig.cmake:28 (find_dependency)
  CMakeLists.txt:257 (find_package)

Reported by:	pkg-fallout

x11-themes/qtcurve/Makefile

@@ -64,8 +64,9 @@ LIB_DEPENDS+=	libqtcurve-utils.so:x11-themes/qtcurve-utils
 .if ${QTCURVE_SLAVE} == "gtk2"
 PKGNAMEPREFIX=	gtk2-
 PKGNAMESUFFIX=	-theme
-USES+=		gettext-runtime gnome kde:5
+USES+=		gettext-runtime gnome kde:5 qt:5
 USE_KDE=	i18n_build
+USE_QT+=	buildtools_build qmake_build
 USE_GNOME=	cairo gdkpixbuf2 gtk20 pango
 USE_LDCONFIG=	yes