When gmake automatically restart itself because one of its includes is updated,

the "MAKEFLAGS" environment variable is no more honoured.

http://savannah.gnu.org/bugs/?30723

diff -rU3 -N make-3.82.orig/main.c make-3.82/main.c

--- main.c.orig	2010-07-19 07:10:53.000000000 +0000

+++ main.c	2014-01-10 10:55:32.000000000 +0000

@@ -2093,7 +2093,7 @@

             const char *pv = define_makeflags (1, 1);

             char *p = alloca (sizeof ("MAKEFLAGS=") + strlen (pv) + 1);

             sprintf (p, "MAKEFLAGS=%s", pv);

-            putenv (p);

+            putenv (allocated_variable_expand (p));

           }

 	  if (ISDB (DB_BASIC))