[Buildroot] [PATCH v2 19/24] opencv: add Qt5 support

[Samuel Martin]

Starting with the 2.4.6 release, OpenCV supports both Qt4 and Qt5,
but only one can be enable at the same time.

Since Buildroot does not support Qt4/Qt5 co-existence, we keep the Qt
support knob as a boolean, but make it depend on BR2_PACKAGE_QT or
BR2_PACKAGE_QT5, and automatically uses the enabled one.

Note that we usually use 'select ...' to express the dependencies
between packages, but in this case, we cannot since the Qt4/Qt5
co-existence exclusion is not handled by a simple choice, but by a
dependency. This makes impossible using 'select ...' for the Qt
support knob without triggering a circular dependency at the kconfig
level.

Besides, we already use 'depends on ...' to express the dependencies
with some "big" packages (like xorg or libgtk2). qt or qt5* packages
are fairly big. So, I don't think it will hurt that much to use a
'depends on ...' statement in this case.

Signed-off-by: Samuel Martin <s.martin49 at gmail.com>

---
changes v1 -> v2:
- rebase
- update threads support dependency for qt5
---
 package/opencv/Config.in | 43 ++++++++++++++++++++++++++++++++-----------
 package/opencv/opencv.mk |  4 ++--
 2 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/package/opencv/Config.in b/package/opencv/Config.in
index 2f47869..8825060 100644
--- a/package/opencv/Config.in
+++ b/package/opencv/Config.in
@@ -181,17 +181,38 @@ config BR2_PACKAGE_OPENCV_WITH_PNG
 	  Use shared libpng from the target system.
 
 config BR2_PACKAGE_OPENCV_WITH_QT
-	bool "qt backend support"
-	depends on BR2_INSTALL_LIBSTDCPP
-	depends on !BR2_avr32 # qt
-	depends on BR2_USE_MMU # qt
-	select BR2_PACKAGE_QT
-	select BR2_PACKAGE_QT_STL
-	select BR2_PACKAGE_QT_GUI_MODULE if BR2_PACKAGE_OPENCV_LIB_HIGHGUI
-	select BR2_PACKAGE_QT_TEST       if BR2_PACKAGE_OPENCV_LIB_HIGHGUI
-	default y
-	help
-	  Use Qt with QtTest module and STL support
+	bool "qt support"
+	depends on (BR2_PACKAGE_QT && !BR2_avr32) || \
+		(BR2_PACKAGE_QT5 && BR2_USE_MMU && BR2_INET_IPV6 && \
+		BR2_TOOLCHAIN_HAS_THREADS_NPTL)
+	select BR2_PACKAGE_QT_STL             if BR2_PACKAGE_QT
+	select BR2_PACKAGE_QT_GUI_MODULE      if BR2_PACKAGE_QT && \
+	                                          BR2_PACKAGE_OPENCV_LIB_HIGHGUI
+	select BR2_PACKAGE_QT_TEST            if BR2_PACKAGE_QT && \
+	                                          BR2_PACKAGE_OPENCV_LIB_HIGHGUI
+	select BR2_PACKAGE_QT5BASE            if BR2_PACKAGE_QT5
+	select BR2_PACKAGE_QT5BASE_CONCURRENT if BR2_PACKAGE_QT5
+	select BR2_PACKAGE_QT5BASE_TEST       if BR2_PACKAGE_QT5
+	select BR2_PACKAGE_QT5BASE_GUI        if BR2_PACKAGE_QT5
+	select BR2_PACKAGE_QT5BASE_WIDGETS    if BR2_PACKAGE_QT5
+	help
+	  Enable Qt support for OpenCV.
+
+	  If Qt4 is already enabled, then use Qt4 with QtTest module and STL
+	  support.
+
+	  If Qt5 is already enabled, then use Qt5 with the following components:
+	  base, concurrent, test, gui and widgets.
+
+if !BR2_PACKAGE_QT && !BR2_PACKAGE_QT5
+comment "qt support with Qt4 needs qt"
+
+comment "qt support with Qt5 needs qt5"
+	depends on BR2_USE_MMU && BR2_INET_IPV6 && BR2_TOOLCHAIN_HAS_THREADS
+
+comment "qt support with Qt5 needs a toolchain w/ wchar, IPv6, theads"
+	depends on !BR2_USE_MMU || !BR2_INET_IPV6 || !BR2_TOOLCHAIN_HAS_THREADS_NPTL
+endif
 
 config BR2_PACKAGE_OPENCV_WITH_TIFF
 	bool "tiff support"
diff --git a/package/opencv/opencv.mk b/package/opencv/opencv.mk
index c4aa967..58bc5c0 100644
--- a/package/opencv/opencv.mk
+++ b/package/opencv/opencv.mk
@@ -207,8 +207,8 @@ OPENCV_CONF_OPT += -DWITH_PNG=OFF
 endif
 
 ifeq ($(BR2_PACKAGE_OPENCV_WITH_QT),y)
-OPENCV_CONF_OPT += -DWITH_QT=4
-OPENCV_DEPENDENCIES += qt
+OPENCV_CONF_OPT += -DWITH_QT=$(if $(BR2_PACKAGE_QT),4,5)
+OPENCV_DEPENDENCIES += $(if $(BR2_PACKAGE_QT),qt,qt5base)
 else
 OPENCV_CONF_OPT += -DWITH_QT=OFF
 endif
-- 
1.9.2