Index: kernel/arch/amd64/Makefile.inc
===================================================================
--- kernel/arch/amd64/Makefile.inc	(revision 26aafe8d909ecb61306a77910aeb374da3814391)
+++ kernel/arch/amd64/Makefile.inc	(revision 0feaae499ef0f72ed8da9eb641f673fab5cbaf7d)
@@ -41,5 +41,5 @@
 # is fixed.
 #
-# If GCC generates a code for tail call, instead of generating ..
+# When GCC generates a code for tail call, instead of generating ..
 #
 #   jmp *fnc
@@ -48,4 +48,6 @@
 #
 #   jmp *$fnc
+#
+# See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48385 for reference.
 #