1 files changed, 17 insertions, 21 deletions
diff --git a/mk/sys.vars.mk b/mk/sys.vars.mk
index f8e6dd7f2c87..7d9cd2f6641f 100644
--- a/mk/sys.vars.mk
+++ b/mk/sys.vars.mk
@@ -1,4 +1,4 @@
-# $Id: sys.vars.mk,v 1.24 2025/11/19 17:44:15 sjg Exp $
+# $Id: sys.vars.mk,v 1.27 2026/03/13 16:02:44 sjg Exp $
 #
 #	@(#) Copyright (c) 2003-2023, Simon J. Gerraty
 #
@@ -24,25 +24,21 @@ MAKE_VERSION ?= 0
 MAKE_VERSION := ${MAKE_VERSION:[1]:C,.*-,,}
 .endif
 
-.if ${MAKE_VERSION} < 20100414
+# from (20260210) .MAKE.VERSION is read-only
+.MAKE.VERSION ?= ${MAKE_VERSION}
+
+.if ${.MAKE.VERSION} < 20100414
 _this = ${.PARSEDIR}/${.PARSEFILE}
 .else
 _this = ${.PARSEDIR:tA}/${.PARSEFILE}
 .endif
 
-# This is a boolean we can use in makefiles as below
-.ifndef MAKE_POSIX_SHELL
-MAKE_POSIX_SHELL != (echo $${PATH%:*}) > /dev/null 2>&1 && echo 1 || echo 0
-.export MAKE_POSIX_SHELL
-.endif
-
-# This is a boolean we can use in target scripts
-.ifndef isPOSIX_SHELL
-.if ${MAKE_POSIX_SHELL}
-isPOSIX_SHELL = :
-.else
-isPOSIX_SHELL = false
-.endif
+# This is a boolean we can use in makefiles:
+#	.if ${isPOSIX_SHELL:U:Nfalse}
+# as well as in target scripts:
+#	if ${isPOSIX_SHELL:Ufalse}; then
+.if empty(isPOSIX_SHELL)
+isPOSIX_SHELL != (echo $${PATH%:*}) > /dev/null 2>&1 && echo : || echo false
 .export isPOSIX_SHELL
 .endif
 
@@ -66,14 +62,14 @@ _type_sh = which
 .endif
 
 # :sh1 evaluates command only once and caches the result.
-.if ${MAKE_VERSION} < 20251111
+.if ${.MAKE.VERSION} < 20251111
 M_sh1 = sh
 .else
 M_sh1 = sh1
 .endif
 
 # AUTOCONF := ${autoconf:L:${M_whence}}
-M_type = @x@(${_type_sh:Utype} $$x) 2> /dev/null; echo;@:${M_sh1:Ush}:[0]:N* found*:[@]:C,[()],,g
+M_type = @x@(${_type_sh:Utype} $x) 2> /dev/null; echo;@:${M_sh1:Ush}:[0]:N* found*:[@]:C,[()],,g
 M_whence = ${M_type}:M/*:[1]
 
 # produce similar output to jot(1) or seq(1)
@@ -98,7 +94,7 @@ M_JOT = [1]:@x@i=1;while [ $$$$i -le $$x ]; do echo $$$$i; i=$$$$((i + 1)); done
 .endif
 
 # ${LIST:${M_RANGE}} is 1 2 3 4 5 if LIST has 5 words
-.if ${MAKE_VERSION} < 20170130
+.if ${.MAKE.VERSION} < 20170130
 M_RANGE = [#]:${M_JOT}
 .else
 M_RANGE = range
@@ -108,7 +104,7 @@ M_RANGE = range
 M_P2V = tu:C,[./-],_,g
 
 # convert path to absolute
-.if ${MAKE_VERSION} < 20100414
+.if ${.MAKE.VERSION} < 20100414
 M_tA = C,.*,('cd' & \&\& 'pwd') 2> /dev/null || echo &,:sh
 .else
 M_tA = tA
@@ -117,7 +113,7 @@ M_tA = tA
 # absoulte path to what we are reading.
 _PARSEDIR = ${.PARSEDIR:${M_tA}}
 
-.if ${MAKE_VERSION} >= 20170130
+.if ${.MAKE.VERSION} >= 20170130
 # M_cmpv allows comparing dotted versions like 3.1.2
 # ${3.1.2:L:${M_cmpv}} -> 3001002
 # we use big jumps to handle 3 digits per dot:
@@ -132,7 +128,7 @@ M_cmpv = S,., ,g:C,^0*([0-9]),\1,:_:range:@i@+ $${_:[-$$i]} \* $${M_cmpv.units:[
 M_M.M.P_VERSION = L:@v@$${MAJOR MINOR PATCH:L:@t@$${$$v_$$t_VERSION:U0}@}@:ts.
 
 # numeric sort
-.if ${MAKE_VERSION} < 20210803
+.if ${.MAKE.VERSION} < 20210803
 M_On = O
 M_Onr = O
 .else