Index: projects/bmake/share/mk/bsd.mkopt.mk
===================================================================
--- projects/bmake/share/mk/bsd.mkopt.mk	(revision 283570)
+++ projects/bmake/share/mk/bsd.mkopt.mk	(revision 283571)
@@ -1,52 +1,85 @@
 #
 # $FreeBSD$
 #
 # Generic mechanism to deal with WITH and WITHOUT options and turn
 # them into MK_ options.
 #
 # For each option FOO in __DEFAULT_YES_OPTIONS, MK_FOO is set to
 # "yes", unless WITHOUT_FOO is defined, in which case it is set to
 # "no".
 #
 # For each option FOO in __DEFAULT_NO_OPTIONS, MK_FOO is set to "no",
 # unless WITH_FOO is defined, in which case it is set to "yes".
 #
 # If both WITH_FOO and WITHOUT_FOO are defined, WITHOUT_FOO wins and
 # MK_FOO is set to "no" regardless of which list it was in.
 #
 # Both __DEFAULT_YES_OPTIONS and __DEFAULT_NO_OPTIONS are undef'd
 # after all this processing, allowing this file to be included
 # multiple times with different lists.
 #
+# Other parts of the build system will set BROKEN_OPTIONS to a list
+# of options that are broken on this platform. This will not be unset
+# before returning. Clients are expected to always += this variable.
+#
 # Users should generally define WITH_FOO or WITHOUT_FOO, but the build
 # system should use MK_FOO={yes,no} when it needs to override the
 # user's desires or default behavior.
 #
 
 #
 # MK_* options which default to "yes".
 #
 .for var in ${__DEFAULT_YES_OPTIONS}
 .if !defined(MK_${var})
 .if defined(WITHOUT_${var})			# WITHOUT always wins
 MK_${var}:=	no
 .else
 MK_${var}:=	yes
 .endif
+.else
+.if ${MK_${var}} != "yes" && ${MK_${var}} != "no"
+.error "Illegal value for MK_${var}: ${MK_${var}}"
 .endif
+.endif # !defined(MK_${var})
 .endfor
 .undef __DEFAULT_YES_OPTIONS
 
 #
 # MK_* options which default to "no".
 #
 .for var in ${__DEFAULT_NO_OPTIONS}
 .if !defined(MK_${var})
 .if defined(WITH_${var}) && !defined(WITHOUT_${var}) # WITHOUT always wins
 MK_${var}:=	yes
 .else
 MK_${var}:=	no
 .endif
+.else
+.if ${MK_${var}} != "yes" && ${MK_${var}} != "no"
+.error "Illegal value for MK_${var}: ${MK_${var}}"
 .endif
+.endif # !defined(MK_${var})
 .endfor
 .undef __DEFAULT_NO_OPTIONS
+
+#
+# MK_* options which are always no, usually because they are
+# unsupported/badly broken on this architecture.
+#
+.for var in ${BROKEN_OPTIONS}
+MK_${var}:=	no
+.endfor
+
+.for vv in ${__DEFAULT_DEPENDENT_OPTIONS}
+.if defined(WITH_${vv:H}) && defined(WITHOUT_${vv:H})
+MK_${vv:H}?= no
+.elif defined(WITH_${vv:H})
+MK_${vv:H}?= yes
+.elif defined(WITHOUT_${vv:H})
+MK_${vv:H}?= no
+.else
+MK_${vv:H}?= ${MK_${vv:T}}
+.endif
+.endfor
+.undef __DEFAULT_DEPENDENT_OPTIONS