Build Qt for OS X and iOS with relative rpath

Defaulting to absolute_library_soname on configure -rpath is no longer
necessary as now we support @rpath install name ids on OS X and iOS.

This also sets QMAKE_SONAME_PREFIX to @rpath for Qt modules when built with
rpath configuration.

This makes Qt libraries relocatable on OS X. Qt SDK is not yet relocatable
though, because plugin location (including cocoa plugin) is still resolved
using absolute path (see QTBUG-14150), also there are several absolute paths
hardcoded in qmake mkspecs pri files.

Task-number: QTBUG-31814
Change-Id: Ie9dffefcd2a946c1580293d433621c1adb7e06c4
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>

configure

@@ -5783,11 +5783,7 @@ fi
 [ '!' -z "$INCLUDES" ] && QMakeVar add INCLUDEPATH "$INCLUDES"
 [ '!' -z "$L_FLAGS" ] && QMakeVar add LIBS "$L_FLAGS"
 
-if [ "$XPLATFORM_MAC" = "yes" ] && [ "$QT_CROSS_COMPILE" = "no" ]; then
-    if [ "$CFG_RPATH" = "yes" ]; then
-       QMAKE_CONFIG="$QMAKE_CONFIG absolute_library_soname"
-    fi
-elif [ -z "`getXQMakeConf 'QMAKE_(LFLAGS_)?RPATH'`" ]; then
+if [ -z "`getXQMakeConf 'QMAKE_(LFLAGS_)?RPATH'`" ]; then
     if [ -n "$RPATH_FLAGS" ]; then
         echo
         echo "ERROR: -R cannot be used on this platform as \$QMAKE_LFLAGS_RPATH is"

mkspecs/features/qt_build_config.prf

@@ -52,12 +52,6 @@ QMAKE_DIR_REPLACE_SANE = PRECOMPILED_DIR OBJECTS_DIR MOC_DIR RCC_DIR UI_DIR
     unset(modpath)
 }
 
-mac {
-   !isEmpty(QMAKE_RPATHDIR){
-       CONFIG += absolute_library_soname
-   }
-}
-
 cross_compile: \
     CONFIG += force_bootstrap
 

mkspecs/features/qt_module.prf

@@ -111,6 +111,9 @@ mac:CONFIG(shared, static|shared):contains(QT_CONFIG, qt_framework) {
    }
 }
 
+mac:contains(QT_CONFIG, rpath): \
+    QMAKE_SONAME_PREFIX = @rpath
+
 mac {
    CONFIG += explicitlib
    macx-g++ {