diff --git a/bin/pax/extern.h b/bin/pax/extern.h
index 298600c2d..94ee13911 100644
--- a/bin/pax/extern.h
+++ b/bin/pax/extern.h
@@ -204,7 +204,6 @@ void options(int, char **);
 OPLIST * opt_next(void);
 int bad_opt(void);
 int mkpath(char *);
-char *chdname;
 #if !HAVE_NBTOOL_CONFIG_H
 int do_chroot;
 #endif
diff --git a/bin/pax/pax.c b/bin/pax/pax.c
index 253d5fc94..24c1112e8 100644
--- a/bin/pax/pax.c
+++ b/bin/pax/pax.c
@@ -116,6 +116,7 @@ int	forcelocal;		/* force local operation even if the name
 				 * contains a :
 				 */
 int	secure = 1;		/* don't extract names that contain .. */
+char *chdname;
 
 /*
  *	PAX - Portable Archive Interchange
diff --git a/external/bsd/llvm/dist/llvm/include/llvm/IR/ValueMap.h b/external/bsd/llvm/dist/llvm/include/llvm/IR/ValueMap.h
index f2ea405f1..45ae7e784 100644
--- a/external/bsd/llvm/dist/llvm/include/llvm/IR/ValueMap.h
+++ b/external/bsd/llvm/dist/llvm/include/llvm/IR/ValueMap.h
@@ -101,7 +101,7 @@ public:
 
   ~ValueMap() {}
 
-  bool hasMD() const { return MDMap; }
+  bool hasMD() const { return (bool)MDMap; }
   MDMapT &MD() {
     if (!MDMap)
       MDMap.reset(new MDMapT);
diff --git a/sbin/newfs_udf/newfs_udf.c b/sbin/newfs_udf/newfs_udf.c
index eaab2b144..10cb32523 100644
--- a/sbin/newfs_udf/newfs_udf.c
+++ b/sbin/newfs_udf/newfs_udf.c
@@ -72,6 +72,9 @@
 int newfs_udf(int argc, char **argv);
 static void usage(void) __attribute__((__noreturn__));
 
+/* shared structure between udf_create.c users */
+struct udf_create_context context;
+struct udf_disclayout     layout;
 
 /* queue for temporary storage of sectors to be written out */
 struct wrsect {
@@ -100,7 +103,6 @@ int	 wrtrack_skew;
 int	 meta_perc = UDF_META_PERC;
 float	 meta_fract = (float) UDF_META_PERC / 100.0;
 
-
 /* --------------------------------------------------------------------- */
 
 /*
diff --git a/sbin/newfs_udf/newfs_udf.h b/sbin/newfs_udf/newfs_udf.h
index 1c21a0b48..e9ff149a5 100644
--- a/sbin/newfs_udf/newfs_udf.h
+++ b/sbin/newfs_udf/newfs_udf.h
@@ -53,8 +53,8 @@ extern float	 meta_fract;
 
 
 /* shared structure between udf_create.c users */
-struct udf_create_context context;
-struct udf_disclayout     layout;
+extern struct udf_create_context context;
+extern struct udf_disclayout     layout;
 
 /* prototypes */
 int udf_write_sector(void *sector, uint64_t location);
diff --git a/usr.bin/make/make.c b/usr.bin/make/make.c
index fde185065..a505fd5d0 100644
--- a/usr.bin/make/make.c
+++ b/usr.bin/make/make.c
@@ -120,6 +120,8 @@ __RCSID("$NetBSD: make.c,v 1.91 2014/10/18 08:33:30 snj Exp $");
 #include    "dir.h"
 #include    "job.h"
 
+FILE *debug_file;
+
 static unsigned int checked = 1;/* Sequence # to detect recursion */
 static Lst     	toBeMade;	/* The current fringe of the graph. These
 				 * are nodes which await examination by
diff --git a/usr.bin/make/make.h b/usr.bin/make/make.h
index f162ef670..e07bba3cc 100644
--- a/usr.bin/make/make.h
+++ b/usr.bin/make/make.h
@@ -440,7 +440,7 @@ extern pid_t	myPid;
  *	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
diff --git a/usr.sbin/installboot/machines.c b/usr.sbin/installboot/machines.c
index 357652b83..508aae92c 100644
--- a/usr.sbin/installboot/machines.c
+++ b/usr.sbin/installboot/machines.c
@@ -46,27 +46,86 @@ __RCSID("$NetBSD: machines.c,v 1.39 2014/02/24 07:23:44 skrll Exp $");
  * isn't built with all the architectures defined.
  * A lot simpler that conditionally including the definitions themselves.
  */
-struct ib_mach
-    ib_mach_alpha,
-    ib_mach_amd64,
-    ib_mach_amiga,
-    ib_mach_emips,
-    ib_mach_ews4800mips,
-    ib_mach_hp300,
-    ib_mach_hppa,
-    ib_mach_i386,
-    ib_mach_landisk,
-    ib_mach_macppc,
-    ib_mach_news68k,
-    ib_mach_newsmips,
-    ib_mach_next68k,
-    ib_mach_pmax,
-    ib_mach_sparc,
-    ib_mach_sparc64,
-    ib_mach_sun2,
-    ib_mach_sun3,
-    ib_mach_vax,
-    ib_mach_x68k;
+// commented out due to modern c not allowing multiple definitions. This will simply throw not defined errors.
+#ifndef __alpha__
+struct ib_mach ib_mach_alpha;
+#endif
+
+#ifndef __amd64__
+struct ib_mach ib_mach_amd64;
+#endif
+
+#ifndef __amiga__
+struct ib_mach ib_mach_amiga;
+#endif
+
+#ifndef __emips__
+struct ib_mach ib_mach_emips;
+#endif
+
+#ifndef __ews4800mips__
+struct ib_mach ib_mach_ews4800mips;
+#endif
+
+#ifndef __hp300__
+struct ib_mach ib_mach_hp300;
+#endif
+
+#ifndef __hppa__
+struct ib_mach ib_mach_hppa;
+#endif
+
+#if !defined(__i386__) && !defined(__amd64__)
+struct ib_mach ib_mach_i386;
+#endif
+
+#ifndef __landisk__
+struct ib_mach ib_mach_landisk;
+#endif
+
+#ifndef __macppc__
+struct ib_mach ib_mach_macppc;
+#endif
+
+#ifndef __news68k__
+struct ib_mach ib_mach_news68k;
+#endif
+
+#ifndef __newsmips__
+struct ib_mach ib_mach_newsmips;
+#endif
+
+#ifndef __next68k__
+struct ib_mach ib_mach_next68k;
+#endif
+
+#ifndef __pmax__
+struct ib_mach ib_mach_pmax;
+#endif
+
+#ifndef __sparc__
+struct ib_mach ib_mach_sparc;
+#endif
+
+#ifndef __sparc64__
+struct ib_mach ib_mach_sparc64;
+#endif
+
+#ifndef __sun2__
+struct ib_mach ib_mach_sun2;
+#endif
+
+#ifndef __sun3__
+struct ib_mach ib_mach_sun3;
+#endif
+
+#ifndef __vax__
+struct ib_mach ib_mach_vax;
+#endif
+
+#ifndef __x68k__
+struct ib_mach ib_mach_x68k;
+#endif
 
 struct ib_mach * const machines[] = {
     &ib_mach_alpha,
diff --git a/usr.sbin/makefs/udf.c b/usr.sbin/makefs/udf.c
index 1ff612ff9..055bd2880 100644
--- a/usr.sbin/makefs/udf.c
+++ b/usr.sbin/makefs/udf.c
@@ -90,6 +90,9 @@ float	 meta_fract = (float) UDF_META_PERC / 100.0;
 int	 mmc_profile;			/* emulated profile */
 int	 req_enable, req_disable;
 
+/* shared structure between udf_create.c users, from sbin/newfs_udf/newfs_udf.h */
+struct udf_create_context context;
+struct udf_disclayout     layout;
 
 /* --------------------------------------------------------------------- */