Back out 218933 and 281934. The easy cases still worked, but some

hard cases broke in worse ways than the status quo.  Back them out
until that can be resolved.

Makefile.inc1

@@ -42,20 +42,6 @@ TARGET_ARCH=${TARGET}
 .include <bsd.own.mk>
 .include <bsd.arch.inc.mk>
 
-# Clang is a special case.  We have to use it to bootstrap the target, not
-# where we're building from.
-.if ${TARGET_ARCH} == i386 || ${TARGET_ARCH} == amd64 || \
-    ${TARGET_ARCH} == arm || ${TARGET_ARCH} == powerpc64 || \
-    ${TARGET_ARCH} == powerpc
-.if !defined(WITHOUT_CLANG)
-MK_CLANG=yes
-.endif
-.else
-.if !defined(WITH_CLANG)
-MK_CLANG=no
-.endif
-.endif
-
 # We must do share/info early so that installation of info `dir'
 # entries works correctly.  Do it first since it is less likely to
 # grow dependencies on include and lib than vice versa.
@@ -984,11 +970,11 @@ _gensnmptree=	usr.sbin/bsnmpd/gensnmptree
 _crunchgen=	usr.sbin/crunch/crunchgen
 .endif
 
-.if ${MK_CLANG} != "no"
+# XXX: There is no way to specify bootstrap tools depending on MK-flags
+# with different per-architecture default values. Always build tblgen.
 _clang_tblgen= \
 	lib/clang/libllvmsupport \
 	usr.bin/clang/tblgen
-.endif
 
 .if ${MK_CDDL} != "no"
 _dtrace_tools= cddl/usr.bin/sgsmsg cddl/lib/libctf lib/libelf \

share/mk/bsd.own.mk

@@ -281,6 +281,18 @@ WITH_HESIOD=
 WITH_IDEA=
 .endif
 
+#
+# Default behaviour of MK_CLANG depends on the architecture.
+#
+.if ${MACHINE_ARCH} == "amd64" || ${MACHINE_ARCH} == "i386" || \
+    ${MACHINE_ARCH} == "powerpc"
+_clang_yes=CLANG
+_clang_no=
+.else
+_clang_yes=
+_clang_no=CLANG
+.endif
+
 #
 # MK_* options which default to "yes".
 #
@@ -301,6 +313,7 @@ WITH_IDEA=
     BIND_MTREE \
     BIND_NAMED \
     BIND_UTILS \
+    BINUTILS \
     BLUETOOTH \
     BOOT \
     BSD_CPIO \
@@ -308,7 +321,7 @@ WITH_IDEA=
     BZIP2 \
     CALENDAR \
     CDDL \
-    CLANG \
+    ${_clang_yes} \
     CPP \
     CRYPT \
     CTM \
@@ -323,6 +336,7 @@ WITH_IDEA=
     FP_LIBC \
     FREEBSD_UPDATE \
     GAMES \
+    GCC \
     GCOV \
     GDB \
     GNU \
@@ -412,6 +426,7 @@ MK_${var}:=	yes
     BIND_SIGCHASE \
     BIND_XML \
     BSD_GREP \
+    ${_clang_no} \
     GPIO \
     HESIOD \
     IDEA