CMake:Android: pass absolute paths to add_jar()

This would make paths in warning/error messages absolute
also, being more clear which module it is from and another
benefit is it being clickable from various IDEs in case the
qt5 repo is opened as a project and not only single modules.

Change-Id: Ic95cea0005f0675186ad700e197e217dad016876
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtJavaHelpers.cmake

@@ -22,7 +22,14 @@ function(qt_internal_add_jar target)
     set(CMAKE_JAVA_COMPILE_FLAGS -source "${javac_source_version}" -target "${javac_target_version}"
         -Xlint:all -classpath "${QT_ANDROID_JAR}"
     )
-    add_jar(${ARGV})
+
+    set(absolute_sources "")
+    foreach(path IN LISTS arg_SOURCES)
+        get_filename_component(absolute_path "${path}" ABSOLUTE)
+        list(APPEND absolute_sources "${absolute_path}")
+    endforeach()
+
+    add_jar(${target} SOURCES ${absolute_sources} ${ARGV})
 
     foreach(f IN LISTS arg_SOURCES)
         _qt_internal_expose_source_file_to_ide(${target} "${f}")