8256810: Incremental rebuild broken on Macosx

Reviewed-by: mikael, ihse

make/common/NativeCompilation.gmk

@@ -237,10 +237,15 @@ ifeq ($(ALLOW_ABSOLUTE_PATHS_IN_OUTPUT)-$(FILE_MACRO_CFLAGS), false-)
         ) \
       )
 
-  # When compiling with relative paths, the deps file comes out with relative
-  # paths.
+  # When compiling with relative paths, the deps file may come out with relative
+  # paths, and that path may start with './'. First remove any leading ./, then
+  # add WORKSPACE_ROOT to any line not starting with /, while allowing for
+  # leading spaces.
   define fix-deps-file
-	$(SED) -e 's|^\([ ]*\)|\1$(WORKSPACE_ROOT)|' $1.tmp > $1
+	$(SED) \
+	    -e 's|^\([ ]*\)\./|\1|' \
+	    -e '/^[ ]*[^/ ]/s|^\([ ]*\)|\1$(WORKSPACE_ROOT)/|' \
+	    $1.tmp > $1
   endef
 else
   # By default the MakeCommandRelative macro does nothing.