Add -qtlibinfix-plugins for renaming Qt plugins according to QT_LIBINFIX

[ChangeLog][configure] Added the configure option -qtlibinfix-plugins
to rename plugins according to QT_LIBINFIX. This option is off by
default.

Fixes: QTBUG-15192
Change-Id: Id5b267e169ee143fc8f7abc6b27bc0ed5306406f
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

config_help.txt

@@ -122,6 +122,7 @@ Build options:
 
   -qtnamespace <name> .. Wrap all Qt library code in 'namespace <name> {...}'.
   -qtlibinfix <infix> .. Rename all libQt5*.so to libQt5*<infix>.so.
+  -qtlibinfix-plugins .. Rename Qt plugins according to -qtlibinfix [no]
 
   -testcocoon .......... Instrument with the TestCocoon code coverage tool [no]
   -gcov ................ Instrument with the GCov code coverage tool [no]

configure.json

@@ -110,6 +110,7 @@
             "profile": "boolean",
             "qreal": "string",
             "qtlibinfix": { "type": "string", "name": "qt_libinfix" },
+            "qtlibinfix-plugins": { "type": "boolean", "name": "qt_libinfix_plugins" },
             "qtnamespace": { "type": "string", "name": "qt_namespace" },
             "reduce-exports": { "type": "boolean", "name": "reduce_exports" },
             "reduce-relocations": { "type": "boolean", "name": "reduce_relocations" },
@@ -1301,6 +1302,12 @@
             "condition": "libs.libudev",
             "output": [ "privateFeature" ]
         },
+        "qt_libinfix_plugins": {
+            "label": "Use QT_LIBINFIX for Plugins",
+            "autoDetect": false,
+            "enable": "input.qt_libinfix != '' && input.qt_libinfix_plugins == 'yes'",
+            "output": [ "privateConfig" ]
+        },
         "compile_examples": {
             "label": "Compile examples",
             "autoDetect": "!config.wasm",

mkspecs/features/qt_plugin.prf

@@ -91,6 +91,7 @@ CONFIG(static, static|shared)|prefix_build {
 target.path = $$[QT_INSTALL_PLUGINS]/$$PLUGIN_TYPE
 INSTALLS += target
 
+qt_libinfix_plugins: TARGET = $$TARGET$$QT_LIBINFIX
 TARGET = $$qt5LibraryTarget($$TARGET)
 
 CONFIG += create_cmake