Various minor cleanups and fixes

The more notable ones are:

src/lib/libast/features/standards:
- Do not redefine _GNU_SOURCE and _FILE_OFFSET_BITS if already
  defined from $CCFLAGS. Thanks to @hyanias for the heads-up.
  (re: 289dd46c)

src/cmd/ksh93/data/builtins.c,
src/cmd/ksh93/include/shell.h,
src/cmd/ksh93/sh/args.c,
src/cmd/ksh93/sh/name.c:
- Remove -T test code activation option. It was basically unused.
  The only thing it did was intentionally introduce a memory leak
  in table_unset() if the 4th bit in the option argument was set.
  A search in ast-open-history reveals a few more trivial test uses
  that were later deleted, but nothing interesting.

src/cmd/ksh93/tests/{basic,path}.sh:
- Skip a couple of tests on AIX avoid hangs, at least one of which
  is not ksh's fault. Thanks to @HansH111 for the report.

src/cmd/ksh93/tests/builtins.sh:
- Change one awk use to a more portable sed invocation to placate
  systems with ancient awk commands, such as AIX. (re: de795e1f)

src/cmd/ksh93/tests/basic.sh

@@ -833,24 +833,27 @@ done
 # ksh2020 regression: https://github.com/att/ast/issues/1284
 actual=$($SHELL --verson 2>&1)
 actual_status=$?
-expect='ksh: verson: bad option(s)'
+expect=': verson: bad option(s)'
 expect_status=2
 [[ "$actual" == *${expect}* ]] || err_exit "failed to handle invalid flag" \
-	"(expected $(printf %q ${expect}*), got $(printf %q "$actual"))"
+	"(expected *$(printf %q "$expect")*, got $(printf %q "$actual"))"
 [[ $actual_status == $expect_status ]] ||
 	err_exit "wrong exit status (expected '$expect_status', got '$actual_status')"
 
 # ======
 # Test for illegal seek error (ksh93v- regression)
 # https://www.mail-archive.com/ast-users@lists.research.att.com/msg00816.html
-if [[ $(uname -s) != SunOS ]]  # Solaris 11.4 join(1) hangs on this test -- not ksh's fault
-then
-exp='1
-2'
-got="$(join <(printf '%d\n' 1 2) <(printf '%d\n' 1 2))"
-[[ $exp == $got ]] || err_exit "pipeline fails with illegal seek error" \
-	"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
-fi  # $(uname -s) != SunOS
+case $(uname -s) in
+AIX | SunOS)
+	# AIX and Solaris join(1) hang on this test -- not ksh's fault
+	;;
+*)
+	exp=$'1\n2'
+	got=$(join <(printf '%d\n' 1 2) <(printf '%d\n' 1 2))
+	[[ $exp == "$got" ]] || err_exit "pipeline fails with illegal seek error" \
+		"(expected $(printf %q "$exp"), got $(printf %q "$got"))"
+	;;
+esac
 
 # ======
 exit $((Errors<125?Errors:125))

src/cmd/ksh93/tests/builtins.sh

@@ -31,7 +31,7 @@ if builtin getconf 2> /dev/null; then
 
 	# The -l option should convert all variable names to lowercase.
 	# https://github.com/att/ast/issues/1171
-	got=$(getconf -lq | awk '{ gsub(/=.*/, "") } /[[:upper:]]/ { print }')
+	got=$(getconf -lq | LC_ALL=C sed -n '/[A-Z].*=/p')
 	[[ -n $got ]] && err_exit "'getconf -l' doesn't convert all variable names to lowercase" \
 		"(got $(printf %q "$got"))"
 

src/cmd/ksh93/tests/path.sh

@@ -795,10 +795,17 @@ PATH=$PWD:$PWD/cmddir $SHELL -c 'noexecute; exit $?'
 got=$?
 [[ $exp == $got ]] || err_exit "Test 3B: failed to run executable command after encountering non-executable command" \
 	"(expected $exp, got $got)"
-PATH=$PWD:$PWD/cmddir $SHELL -ic 'noexecute; exit $?'
-got=$?
-[[ $exp == $got ]] || err_exit "Test 3C: failed to run executable command after encountering non-executable command" \
-	"(expected $exp, got $got)"
+case $(uname -s) in
+AIX)
+	# ksh -ic hangs on AIX
+	;;
+*)
+	PATH=$PWD:$PWD/cmddir $SHELL -ic 'noexecute; exit $?'
+	got=$?
+	[[ $exp == $got ]] || err_exit "Test 3C: failed to run executable command after encountering non-executable command" \
+		"(expected $exp, got $got)"
+	;;
+esac
 PATH=$PWD:$PWD/cmddir $SHELL -c 'command -x noexecute; exit $?'
 got=$?
 [[ $exp == $got ]] || err_exit "Test 3D: failed to run executable command after encountering non-executable command" \