separate out the arch-specific and compat-specific subdirs.
put compat stuff in NetBSD.compat.$MACHINE_ARCH, and normal
stuff in NetBSD.dist.$MACHINE/MACHINE_ARCH, etc.

probably need at at more files for sh3, mips, ppc, sparc,
m68k, arm, ia64, etc., as every port has port- or arch-
specific header subdirectory.


Index: Makefile
===================================================================
RCS file: /cvsroot/src/etc/mtree/Makefile,v
retrieving revision 1.38
diff -p -u -r1.38 Makefile
--- Makefile	9 Feb 2019 02:04:19 -0000	1.38
+++ Makefile	9 Feb 2019 12:55:23 -0000
@@ -10,10 +10,8 @@ EXTRA_DIST_FILES=	NetBSD.dist.Xorg
 # by something else; this may need to be fixed properly in the future.
 .if defined(MKCOMPAT) && ${MKCOMPAT} != "no"
 .include "${NETBSDSRCDIR}/compat/archdirs.mk"
-.if exists(NetBSD.dist.${MACHINE_ARCH})
-EXTRA_DIST_FILES+=	NetBSD.dist.${MACHINE_ARCH}
-.elif !empty(MACHINE_ARCH:Mearm*)
-EXTRA_DIST_FILES+=	NetBSD.dist.earm
+.if exists(NetBSD.compat.${MACHINE_ARCH})
+EXTRA_DIST_FILES+=	NetBSD.compat.${MACHINE_ARCH}
 .endif
 EXTRA_DIST_FILES+=	NetBSD.dist.compat	# autogenerated
 .if defined(MKCOMPATX11) && ${MKCOMPATX11} != "no" && ${MKX11} != "no"
@@ -21,6 +19,10 @@ EXTRA_DIST_FILES+=	NetBSD.dist.xcompat	#
 .endif
 .endif
 
+.if exists(NetBSD.dist.${MACHINE_ARCH})
+EXTRA_DIST_FILES+=	NetBSD.dist.${MACHINE_ARCH}
+.endif
+
 .if exists(NetBSD.dist.${MACHINE})
 EXTRA_DIST_FILES+=	NetBSD.dist.${MACHINE}
 .endif
Index: NetBSD.compat.aarch64
===================================================================
RCS file: NetBSD.compat.aarch64
diff -N NetBSD.compat.aarch64
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.aarch64	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,4 @@
+# $NetBSD: NetBSD.dist.aarch64,v 1.4 2018/07/17 00:50:56 christos Exp $
+
+./usr/include/g++/bits/arm
+./usr/include/g++/bits/aarch64
Index: NetBSD.compat.mips64eb
===================================================================
RCS file: NetBSD.compat.mips64eb
diff -N NetBSD.compat.mips64eb
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.mips64eb	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,5 @@
+#	$NetBSD: NetBSD.dist.mips64eb,v 1.9 2015/06/19 18:16:06 matt Exp $
+
+./usr/include/g++/bits/mips64
+./usr/include/g++/bits/mips32
+./usr/include/g++/bits/mipso32
Index: NetBSD.compat.mips64el
===================================================================
RCS file: NetBSD.compat.mips64el
diff -N NetBSD.compat.mips64el
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.mips64el	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,5 @@
+#	$NetBSD: NetBSD.dist.mips64el,v 1.10 2015/06/19 18:16:06 matt Exp $
+
+./usr/include/g++/bits/mips64
+./usr/include/g++/bits/mips32
+./usr/include/g++/bits/mipso32
Index: NetBSD.compat.powerpc64
===================================================================
RCS file: NetBSD.compat.powerpc64
diff -N NetBSD.compat.powerpc64
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.powerpc64	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,4 @@
+#	$NetBSD: NetBSD.dist.powerpc64,v 1.3 2015/06/19 18:16:06 matt Exp $
+
+./usr/include/g++/bits/powerpc
+./usr/include/g++/bits/powerpc64
Index: NetBSD.compat.riscv64
===================================================================
RCS file: NetBSD.compat.riscv64
diff -N NetBSD.compat.riscv64
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.riscv64	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,4 @@
+# $NetBSD: NetBSD.dist.riscv64,v 1.2 2015/06/19 18:16:06 matt Exp $
+
+./usr/include/g++/bits/riscv32
+./usr/include/g++/bits/riscv64
Index: NetBSD.compat.sparc64
===================================================================
RCS file: NetBSD.compat.sparc64
diff -N NetBSD.compat.sparc64
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.sparc64	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,4 @@
+#	$NetBSD: NetBSD.dist.sparc64,v 1.10 2015/06/19 18:16:06 matt Exp $
+
+./usr/include/g++/bits/sparc
+./usr/include/g++/bits/sparc64
Index: NetBSD.compat.x86_64
===================================================================
RCS file: NetBSD.compat.x86_64
diff -N NetBSD.compat.x86_64
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.compat.x86_64	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,4 @@
+#	$NetBSD: NetBSD.dist.x86_64,v 1.12 2019/02/08 23:27:14 mrg Exp $
+
+./usr/include/g++/bits/i386
+./usr/include/g++/bits/x86_64
Index: NetBSD.dist.aarch64
===================================================================
RCS file: NetBSD.dist.aarch64
diff -N NetBSD.dist.aarch64
--- NetBSD.dist.aarch64	17 Jul 2018 00:50:56 -0000	1.4
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,4 +0,0 @@
-# $NetBSD: NetBSD.dist.aarch64,v 1.4 2018/07/17 00:50:56 christos Exp $
-
-./usr/include/g++/bits/arm
-./usr/include/g++/bits/aarch64
Index: NetBSD.dist.earm
===================================================================
RCS file: NetBSD.dist.earm
diff -N NetBSD.dist.earm
--- NetBSD.dist.earm	19 Jun 2015 18:16:06 -0000	1.3
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,2 +0,0 @@
-#	$NetBSD: NetBSD.dist.earm,v 1.3 2015/06/19 18:16:06 matt Exp $
-
Index: NetBSD.dist.m68k
===================================================================
RCS file: NetBSD.dist.m68k
diff -N NetBSD.dist.m68k
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ NetBSD.dist.m68k	9 Feb 2019 12:55:23 -0000
@@ -0,0 +1,3 @@
+#	$NetBSD$
+
+./usr/include/m68k
Index: NetBSD.dist.mips64eb
===================================================================
RCS file: NetBSD.dist.mips64eb
diff -N NetBSD.dist.mips64eb
--- NetBSD.dist.mips64eb	19 Jun 2015 18:16:06 -0000	1.9
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,5 +0,0 @@
-#	$NetBSD: NetBSD.dist.mips64eb,v 1.9 2015/06/19 18:16:06 matt Exp $
-
-./usr/include/g++/bits/mips64
-./usr/include/g++/bits/mips32
-./usr/include/g++/bits/mipso32
Index: NetBSD.dist.mips64el
===================================================================
RCS file: NetBSD.dist.mips64el
diff -N NetBSD.dist.mips64el
--- NetBSD.dist.mips64el	19 Jun 2015 18:16:06 -0000	1.10
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,5 +0,0 @@
-#	$NetBSD: NetBSD.dist.mips64el,v 1.10 2015/06/19 18:16:06 matt Exp $
-
-./usr/include/g++/bits/mips64
-./usr/include/g++/bits/mips32
-./usr/include/g++/bits/mipso32
Index: NetBSD.dist.powerpc64
===================================================================
RCS file: NetBSD.dist.powerpc64
diff -N NetBSD.dist.powerpc64
--- NetBSD.dist.powerpc64	19 Jun 2015 18:16:06 -0000	1.3
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,4 +0,0 @@
-#	$NetBSD: NetBSD.dist.powerpc64,v 1.3 2015/06/19 18:16:06 matt Exp $
-
-./usr/include/g++/bits/powerpc
-./usr/include/g++/bits/powerpc64
Index: NetBSD.dist.riscv64
===================================================================
RCS file: NetBSD.dist.riscv64
diff -N NetBSD.dist.riscv64
--- NetBSD.dist.riscv64	19 Jun 2015 18:16:06 -0000	1.2
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,4 +0,0 @@
-# $NetBSD: NetBSD.dist.riscv64,v 1.2 2015/06/19 18:16:06 matt Exp $
-
-./usr/include/g++/bits/riscv32
-./usr/include/g++/bits/riscv64
Index: NetBSD.dist.sparc64
===================================================================
RCS file: NetBSD.dist.sparc64
diff -N NetBSD.dist.sparc64
--- NetBSD.dist.sparc64	19 Jun 2015 18:16:06 -0000	1.10
+++ /dev/null	1 Jan 1970 00:00:00 -0000
@@ -1,4 +0,0 @@
-#	$NetBSD: NetBSD.dist.sparc64,v 1.10 2015/06/19 18:16:06 matt Exp $
-
-./usr/include/g++/bits/sparc
-./usr/include/g++/bits/sparc64
Index: NetBSD.dist.x86_64
===================================================================
RCS file: /cvsroot/src/etc/mtree/NetBSD.dist.x86_64,v
retrieving revision 1.12
diff -p -u -r1.12 NetBSD.dist.x86_64
--- NetBSD.dist.x86_64	8 Feb 2019 23:27:14 -0000	1.12
+++ NetBSD.dist.x86_64	9 Feb 2019 12:55:23 -0000
@@ -3,8 +3,6 @@
 ./usr/include/amd64
 ./usr/include/dev/nvmm
 ./usr/include/dev/nvmm/x86
-./usr/include/g++/bits/i386
-./usr/include/g++/bits/x86_64
 ./usr/include/i386
 ./usr/include/x86
 ./usr/include/xen