diff --git a/kdevplatform/cmake/modules/KDevPlatformMacros.cmake b/kdevplatform/cmake/modules/KDevPlatformMacros.cmake
--- a/kdevplatform/cmake/modules/KDevPlatformMacros.cmake
+++ b/kdevplatform/cmake/modules/KDevPlatformMacros.cmake
@@ -66,12 +66,12 @@
             set(extraArgs "")
             if(DEFINED ENV{SOURCE_DATE_EPOCH})
                 # We assume there is tar > 1.28 if a reproducible build is wanted.
-                set(extraArgs --mtime=$ENV{SOURCE_DATE_EPOCH} --sort=name)
+                set(extraArgs --mtime="@$ENV{SOURCE_DATE_EPOCH}" --sort=name)
             endif()
             add_custom_command(OUTPUT ${_template}
                 COMMAND tar ARGS -c -C ${CMAKE_CURRENT_SOURCE_DIR}/${_templateName}
-                    --exclude .kdev_ignore --exclude .svn --mode=go=rX,u+rw,a-s --owner=root 
-                    --group=root --numeric-owner -j -f ${_template} ${extraArgs} .
+                    --exclude .kdev_ignore --exclude .svn --mode=go=rX,u+rw,a-s
+                    --owner=0 --group=0 --numeric-owner -j -f ${_template} ${extraArgs} .
                 DEPENDS ${_deps}
             )
         endif()