qt: fix plugin installation and change plugin path

Since the conversion of Qt to GENTARGETS in
421cda1fd078f5fa7902f05bd1d2021fd101d9ea, plugin installation could
break in some situations, for example if SQL support was enabled, but
without any SQL driver: the sql plugin directory doesn't exist, but
our qt.mk wanted to copy it.

This patches simplifies the plugin handling a bit, and basically
copies all Qt plugins installed in the $(STAGING_DIR) to the
$(TARGET_DIR), assuming Qt has only built and installed the needed
plugins.

Moreover, instead of installing plugins to usr/plugins, which is a odd
location, we install them in usr/lib/qt/plugins. This requires a small
patch to Qt ./configure script so that even when -hostprefix is used,
the -plugindir option is taken into account.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/qt/qt-4.7.2-configure.patch

@@ -0,0 +1,48 @@
+Fix -hostprefix behaviour
+
+When -hostprefix ./configure option is used, Qt installs all its
+headers, libraries and binaries inside the given host prefix, instead
+of the prefix. This is used by Buildroot to make sure that all Qt
+libraries and headers are installed in $(STAGING_DIR).
+
+Qt ./configure script also allows to tune the installation location of
+various elements, for examples the plugins through the -plugindir
+option. Unfortunately, this option only impact the installation path
+on the target, but not on the host when -hostprefix is used.
+
+This patch modifies Qt ./configure script so that HOST_*PATH_STR
+variables are composed of the host prefix concatenated with the path
+of installation on the target. This way, the plugin installation local
+in the $(STAGING_DIR) and on the target remains the same.
+
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+
+Index: qt-4.7.2/configure
+===================================================================
+--- qt-4.7.2.orig/configure	2011-03-31 22:28:16.530647168 +0200
++++ qt-4.7.2/configure	2011-03-31 22:29:38.908081695 +0200
+@@ -4456,15 +4456,15 @@
+
+
+ if [ ! -z "$QT_HOST_PREFIX" ]; then
+-    HOSTPREFIX_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_prfxpath=$QT_HOST_PREFIX"`
+-    HOSTDOCUMENTATION_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_docspath=$QT_HOST_PREFIX/doc"`
+-    HOSTHEADERS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_hdrspath=$QT_HOST_PREFIX/include"`
+-    HOSTLIBRARIES_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_libspath=$QT_HOST_PREFIX/lib"`
+-    HOSTBINARIES_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_binspath=$QT_HOST_PREFIX/bin"`
+-    HOSTPLUGINS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_plugpath=$QT_HOST_PREFIX/plugins"`
+-    HOSTIMPORTS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_impspath=$QT_HOST_PREFIX/IMPORTS"`
+-    HOSTDATA_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_datapath=$QT_HOST_PREFIX"`
+-    HOSTTRANSLATIONS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_trnspath=$QT_HOST_PREFIX/translations"`
++    HOSTPREFIX_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_prfxpath=$QT_HOST_PREFIX/$QT_INSTALL_PREFIX"`
++    HOSTDOCUMENTATION_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_docspath=$QT_HOST_PREFIX/$QT_INSTALL_DOCS"`
++    HOSTHEADERS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_hdrspath=$QT_HOST_PREFIX/$QT_INSTALL_HEADERS"`
++    HOSTLIBRARIES_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_libspath=$QT_HOST_PREFIX/$QT_INSTALL_LIBS"`
++    HOSTBINARIES_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_binspath=$QT_HOST_PREFIX/$QT_INSTALL_BINS"`
++    HOSTPLUGINS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_plugpath=$QT_HOST_PREFIX/$QT_INSTALL_PLUGINS"`
++    HOSTIMPORTS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_impspath=$QT_HOST_PREFIX/$QT_INSTALL_IMPORTS"`
++    HOSTDATA_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_datapath=$QT_HOST_PREFIX/$QT_INSTALL_DATA"`
++    HOSTTRANSLATIONS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_trnspath=$QT_HOST_PREFIX/$QT_INSTALL_TRANSLATIONS"`
+     HOSTSETTINGS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_stngpath=$QT_INSTALL_SETTINGS"`
+     HOSTEXAMPLES_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_xmplpath=$QT_INSTALL_EXAMPLES"`
+     HOSTDEMOS_PATH_STR=`"$relpath/config.tests/unix/padstring" 268 "qt_demopath=$QT_INSTALL_DEMOS"`

package/qt/qt.mk

@@ -481,7 +481,8 @@ define QT_CONFIGURE_CMDS
 		-no-accessibility \
 		-no-separate-debug-info \
 		-prefix /usr \
-		-hostprefix $(STAGING_DIR)/usr \
+		-plugindir /usr/lib/qt/plugins \
+		-hostprefix $(STAGING_DIR) \
 		-fast \
 		-no-rpath \
 	)
@@ -499,23 +500,19 @@ QT_HOST_PROGRAMS   += moc rcc qmake lrelease
 
 ifeq ($(BR2_PACKAGE_QT_GUI_MODULE),y)
 QT_INSTALL_LIBS    += QtGui
-QT_INSTALL_PLUGINS += imageformats
 QT_HOST_PROGRAMS   += uic
 endif
 ifeq ($(BR2_PACKAGE_QT_SQL_MODULE),y)
 QT_INSTALL_LIBS    += QtSql
-QT_INSTALL_PLUGINS += sqldrivers
 endif
 ifeq ($(BR2_PACKAGE_QT_MULTIMEDIA),y)
 QT_INSTALL_LIBS    += QtMultimedia
 endif
 ifeq ($(BR2_PACKAGE_QT_PHONON),y)
 QT_INSTALL_LIBS    += phonon
-QT_INSTALL_PLUGINS += phonon_backend
 endif
 ifeq ($(BR2_PACKAGE_QT_SVG),y)
 QT_INSTALL_LIBS    += QtSvg
-QT_INSTALL_PLUGINS += iconengines
 endif
 ifeq ($(BR2_PACKAGE_QT_NETWORK),y)
 QT_INSTALL_LIBS    += QtNetwork
@@ -582,10 +579,10 @@ endif
 
 # Plugin installation
 define QT_INSTALL_TARGET_PLUGINS
-	for plugin in $(QT_INSTALL_PLUGINS); do \
-		mkdir -p $(TARGET_DIR)/usr/plugins ; \
-		cp -dpfr $(STAGING_DIR)/usr/plugins/$$plugin $(TARGET_DIR)/usr/plugins/; \
-	done
+	if [ -d $(STAGING_DIR)/usr/lib/qt/plugins/ ] ; then \
+		mkdir -p $(TARGET_DIR)/usr/lib/qt/plugins ; \
+		cp -dpfr $(STAGING_DIR)/usr/lib/qt/plugins/* $(TARGET_DIR)/usr/lib/qt/plugins ; \
+	fi
 endef
 
 # Fonts installation