diff --git a/Brewfile b/Brewfile
index c22487e041..953b28a583 100644
--- a/Brewfile
+++ b/Brewfile
@@ -8,6 +8,7 @@
 # changing it automatically invalidates the cache.
 
 brew "autoconf"
+brew "bison"
 brew "coreutils"
 brew "gnu-tar"
 brew "libuv"
diff --git a/configure b/configure
index 4a94419960..dfd062ad9f 100755
--- a/configure
+++ b/configure
@@ -912,6 +912,7 @@ echo_n
 sort
 RAGEL
 yacc
+yacc_prog
 YFLAGS
 YACC
 lex
@@ -3163,8 +3164,8 @@ ac_cxx_conftest_cxx11_main='
 }
 {
   // Unicode literals
-  auto const *utf8 = u8"UTF-8 string \u2500";
-  char16_t const *utf16 = u"UTF-16 string \u2500";
+  char const *utf8 = u8"UTF-8 string \u2500";
+  char16_t const *utf16 = u"UTF-8 string \u2500";
   char32_t const *utf32 = U"UTF-32 string \u2500";
 }
 '
@@ -6342,16 +6343,86 @@ fi
 done
 test -n "$YACC" || YACC="yacc"
 
-yacc=`$echo $YACC | awk '{print $1}'`
-yacc=`$which "$yacc"`
-if test ! -x "$yacc"; then
+yacc_prog=`$echo $YACC | awk '{print $1}'`
+if test "$yacc_prog" = bison
+then
+    case "$host_os"
+    in
+	darwin*)
+								bison_extra_path=
+		brew_bison=`brew --prefix bison 2>/dev/null`/bin
+		test -d "$brew_bison" && bison_extra_path="$brew_bison$PATH_SEPARATOR"
+		for ac_prog in bison
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_path_yacc_prog+y}
+then :
+  printf %s "(cached) " >&6
+else case e in #(
+  e) case $yacc_prog in
+  [\\/]* | ?:[\\/]*)
+  ac_cv_path_yacc_prog="$yacc_prog" # Let the user override the test with a path.
+  ;;
+  *)
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $bison_extra_path$PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_path_yacc_prog="$as_dir$ac_word$ac_exec_ext"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+  ;;
+esac ;;
+esac
+fi
+yacc_prog=$ac_cv_path_yacc_prog
+if test -n "$yacc_prog"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $yacc_prog" >&5
+printf "%s\n" "$yacc_prog" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$yacc_prog" && break
+done
+test -n "$yacc_prog" || yacc_prog="no"
+
+		;;
+	*)
+		yacc_prog=`$which "$yacc_prog"`
+    esac
+else
+    yacc_prog=`$which "$yacc_prog"`
+fi
+
+if test ! -x "$yacc_prog"; then
     as_fn_error $? "cannot find a valid 'yacc'/'bison' command." "$LINENO" 5
 fi
-yacc=`echo $YACC | sed -e '/^bison /{
-s/$/ /
-s/ -y / /
-s/ $//
-}'`
+yacc=`echo $YACC | $AWK '
+    { printf "'"$yacc_prog"'"
+      for (i = 2; i <= NF; i++) {
+	if ($1 == "bison" && $i == "-y") continue
+	printf " %s", $i
+      }
+      printf "\n"
+    }'`
 
 
 for ac_prog in ragel
diff --git a/configure.ac b/configure.ac
index 365b24daa0..9c301161c4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -746,17 +746,40 @@ lex=$LEX
 AC_SUBST(lex)
 
 AC_PROG_YACC
-yacc=`$echo $YACC | awk '{print $1}'`
-yacc=`$which "$yacc"`
-if test ! -x "$yacc"; then
+yacc_prog=`$echo $YACC | awk '{print $1}'`
+if test "$yacc_prog" = bison
+then
+    case "$host_os"
+    in
+	darwin*)
+		dnl want homebrew bison, but it is keg-only (so bin dir is
+		dnl "hidden" and bison-specific) ... because libpcp will not
+		dnl compile with the bison v2.3 from macOS default install
+		bison_extra_path=
+		brew_bison=`brew --prefix bison 2>/dev/null`/bin
+		test -d "$brew_bison" && bison_extra_path="$brew_bison$PATH_SEPARATOR"
+		AC_PATH_PROGS([yacc_prog], [bison], [no], [$bison_extra_path$PATH])
+		;;
+	*)
+		yacc_prog=`$which "$yacc_prog"`
+    esac
+else
+    yacc_prog=`$which "$yacc_prog"`
+fi
+
+if test ! -x "$yacc_prog"; then
     AC_MSG_ERROR([cannot find a valid 'yacc'/'bison' command.])
 fi
-dnl if this is bison, don't use the -y option
-yacc=`echo $YACC | sed -e '/^bison /{
-s/$/ /
-s/ -y / /
-s/ $//
-}'`
+dnl append any command line options from $YACC, but if this is bison
+dnl do not use the -y (yacc) option
+yacc=`echo $YACC | $AWK '
+    { printf "'"$yacc_prog"'"
+      for (i = 2; i <= NF; i++) {
+	if ($1 == "bison" && $i == "-y") continue
+	printf " %s", $i
+      }
+      printf "\n"
+    }'`
 AC_SUBST(yacc)
 
 AC_CHECK_PROGS(RAGEL, ragel, [])
diff --git a/qa/admin/package-lists/Darwin+25+arm64 b/qa/admin/package-lists/Darwin+25+arm64
index 8f8186b5f9..98a87df9ca 100644
--- a/qa/admin/package-lists/Darwin+25+arm64
+++ b/qa/admin/package-lists/Darwin+25+arm64
@@ -13,6 +13,8 @@ YAML::XS cpan
 # brew formula or casks for building and git activity and QA
 #
 autoconf brew
+bison brew
+cmocka brew
 coreutils brew
 docker brew
 gawk brew
@@ -20,7 +22,6 @@ gdb brew
 # github is kinda strange ... it is brew-installed but not reported
 # by brew formulae nor brew casks
 # github brew
-cmocka brew
 hub brew
 libvirt brew
 libuv brew
diff --git a/qa/admin/pcp-daily b/qa/admin/pcp-daily
index c5c4ffd737..c65203a396 100755
--- a/qa/admin/pcp-daily
+++ b/qa/admin/pcp-daily
@@ -1224,18 +1224,21 @@ End-of-File
 	    scp $qa_user@$host:daily.harvest $tmp.harvest >$tmp.out 2>&1
 	    if [ -s $tmp.harvest ]
 	    then
+		pfx=''
 		for file in `cat $tmp.harvest`
 		do
-		    echo -n " $file"
+		    printf '%s' "$pfx$file"
+		    pfx=' '
 		    if scp $qa_user@$host:$qa_dir/$file $HOME/Logs/by-vm/$host/qa >$tmp.err 2>&1
 		    then
 			:
 		    else
-			echo
+			printf '\n'
 			cat $tmp.err
+			pfx=''
 		    fi
 		done
-		echo
+		[ "$pfx" = ' ' ] && printf '\n'
 	    elif [ -s $tmp.out ]
 	    then
 		echo "scp error ..."
diff --git a/src/pmcd/rc_pmcd b/src/pmcd/rc_pmcd
index d3300442e5..1675c18ecb 100644
--- a/src/pmcd/rc_pmcd
+++ b/src/pmcd/rc_pmcd
@@ -173,15 +173,58 @@ _pmda_setup()
 {
     # Auto-Install and/or Auto-Remove PMDAs?
     #
+    __try=10
+    while [ -f $PCP_PMDAS_DIR/pmda.auto.update ]
+    do
+	# lock file exists, if it is stale, remove it ... a concurrent
+	# rc_pmcd could remove it while we're checking, so silently ignore
+	# failure to remove the lock file
+	#
+	__pid=`$PCP_AWK_PROG <$PCP_PMDAS_DIR/pmda.auto.update 2>/dev/null '{ print $1 }'`
+	__pname=`$PCP_AWK_PROG <$PCP_PMDAS_DIR/pmda.auto.update 2>/dev/null '{ print $2 }'`
+	if [ -z "$__pname" -o -z "$__pid" ]
+	then
+	    # possible race on startup ... the lock file may be empty
+	    # so wait a while, but don't wait forever
+	    #
+	    if [ $__try -gt 0 ]
+	    then
+		__try=`expr $__try - 1`
+		sleep 1
+		continue
+	    else
+		if rm $PCP_PMDAS_DIR/pmda.auto.update >/dev/null 2>&1
+		then
+		    $PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ stale pmda.auto.update lock removed, empty and not changing after 10secs"
+		fi
+	    fi
+	fi
+	if [ "$__pname" != rc_pmcd ]
+	then
+	    if rm $PCP_PMDAS_DIR/pmda.auto.update >/dev/null 2>&1
+	    then
+		$PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ stale pmda.auto.update lock removed, bogus owner ($__pname) not rc_pmcd"
+	    fi
+	elif [ -n "$__pid" ]
+	then
+	    if ! $PCP_PS_PROG -p "$__pid" >/dev/null 2>&1
+	    then
+		if rm $PCP_PMDAS_DIR/pmda.auto.update >/dev/null 2>&1
+		then
+		    $PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ stale pmda.auto.update lock removed, owner process (pid=$__pid) has vanished"
+		fi
+	    fi
+	fi
+    done
     if $PCP_BINADM_DIR/pmlock -i "$$ rc_pmcd" $PCP_PMDAS_DIR/pmda.auto.update
     then
 	# we got the lock, proceed
-	$PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ acquire lock"
+	$PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ acquire pmda.auto.update lock"
 	:
     else
 	# one of us is already running
 	#
-	$PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ lock failed"
+	$PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ pmda.auto.update lock failed: `ls -l $PCP_PMDAS_DIR/pmda.auto.update`"
 	return
     fi
 
@@ -199,7 +242,7 @@ _pmda_setup()
     fi
 
     rm -f $PCP_PMDAS_DIR/pmda.auto.update
-    $PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ release lock"
+    $PCP_BINADM_DIR/pmpost "PMDA setup: pid=$$ release pmda.auto.update lock"
 
     # re-instate mainline trap
     #