diff -ru bmake.orig/job.c bmake/job.c
--- bmake.orig/job.c	2020-04-09 14:03:57.232919836 +0200
+++ bmake/job.c	2020-06-14 22:19:09.776490793 +0200
@@ -180,6 +180,8 @@
 #define ABORT_WAIT	3   	    /* Waiting for jobs to finish */
 #define JOB_TOKENS	"+EI+"	    /* Token to requeue for each abort state */
 
+FILE *debug_file;
+
 /*
  * this tracks the number of tokens currently "out" to build jobs.
  */
diff -ru bmake.orig/make.h bmake/make.h
--- bmake.orig/make.h	2020-02-10 18:07:01.708744511 +0100
+++ bmake/make.h	2020-06-14 22:18:24.965773603 +0200
@@ -464,7 +464,7 @@
  *	There is one bit per module.  It is up to the module what debug
  *	information to print.
  */
-FILE *debug_file;		/* Output written here - default stdout */
+extern FILE *debug_file;	/* Output written here - default stdout */
 extern int debug;
 #define	DEBUG_ARCH	0x00001
 #define	DEBUG_COND	0x00002