Resolve "`Util/Util.cpp` always compiled (Follow-up from "Resolve "better solution to create/update src/OPALrevision.h")"

Closes #560 (closed)

gen_OPALrevision

@@ -4,7 +4,12 @@
 #
 
 print () {
-    echo '#define GIT_VERSION '\"$1\" > src/OPALrevision.h
+    echo '#define GIT_VERSION '\"$1\" > src/OPALrevision-new.h
+    if [[ -e  src/OPALrevision.h ]] && cmp -s src/OPALrevision.h src/OPALrevision-new.h; then
+        rm src/OPALrevision-new.h
+    else
+        mv src/OPALrevision-new.h src/OPALrevision.h
+    fi
 }
 
 # if git(1) is not in $PATH
@@ -16,7+21,7 @@
         # otherwise create file
         print unknown
         exit $?
     fi
 fi
 
 # if we are in a work-tree