qwt: add optional opengl support

qwt should only build the opengl support code if Qt is configured with
opengl support, so add a suboption for it similar to svg/mathml with the
needed dependencies.

Fixes http://autobuild.buildroot.net/results/597/5977bd77342e28ae9783f9f9edfcf84eefd081b6/

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/qwt/Config.in

@@ -16,6 +16,12 @@ config BR2_PACKAGE_QWT_SVG
 config BR2_PACKAGE_QWT_MATHML
 	bool "MathML support"
 
+config BR2_PACKAGE_QWT_OPENGL
+	bool "OpenGL support"
+	depends on BR2_PACKAGE_HAS_LIBGLES
+	depends on BR2_PACKAGE_HAS_LIBEGL
+	select BR2_PACKAGE_QT_OPENGL_ES
+
 endif
 
 comment "qwt depends on QT gui module"

package/qwt/qwt.mk

@@ -26,6 +26,12 @@ else
 	QWT_CONFIG += -e 's/^.*QWT_CONFIG.*QwtMathML.*$$/\# QWT_CONFIG += QwtMathML/'
 endif
 
+ifeq ($(BR2_PACKAGE_QWT_OPENGL),y)
+	QWT_CONFIG += -e 's/^.*QWT_CONFIG.*QwtOpenGL.*$$/QWT_CONFIG += QwtOpenGL/'
+else
+	QWT_CONFIG += -e 's/^.*QWT_CONFIG.*QwtOpenGL.*$$/\# QWT_CONFIG += QwtOpenGL/'
+endif
+
 define QWT_CONFIGURE_CMDS
 	$(SED) $(QWT_CONFIG) $(@D)/qwtconfig.pri
 	(cd $(@D); $(TARGET_MAKE_ENV) $(QT_QMAKE))