Squashed commit of the following:

commit 61f2a5e0e48e050b8f73b127202af068b8cb574b
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 24 11:08:22 2022 +0300

    Update awkcard.in.

commit 2b84c068b0568b4efaf93f9f6ffeaf2105295de7
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Wed Jun 22 22:02:59 2022 +0300

    A few more small doc updates.

commit ce3bb88b7e71e1185c243bcc22cdcc7dbb250988
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Wed Jun 22 10:33:08 2022 +0300

    Doc updates.

commit 0c101d168279d1400d3954a84a231ee70862ab61
Merge: 78fd9d6f d43b469f
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Wed Jun 22 10:19:58 2022 +0300

    Merge branch 'master' into feature/pma2

commit 78fd9d6f1f45688d32e77ed7eb8cb18f9a140ec8
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Mon Jun 20 08:48:35 2022 +0300

    Add --persist option.

commit a6253b1b2f3eba98a42c8b39d4af8916187d7249
Merge: bedd2e70 03f79dcb
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Mon Jun 20 08:43:28 2022 +0300

    Merge branch 'master' into feature/pma2

commit bedd2e706af48057805b5221886912545c16f193
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 17 14:40:33 2022 +0300

    Fix support/ChangeLog.

commit 8da00d7e8666808ffa50ae654b5498c4ca4b7d8c
Merge: 882a6b67 f2e71851
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 17 14:39:48 2022 +0300

    Merge branch 'master' into feature/pma2

commit 882a6b67547204800ca865b530e3f8ef51ebd20c
Merge: 5c689dd7 ae879ed7
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 17 14:16:36 2022 +0300

    Merge branch 'master' into feature/pma2

commit 5c689dd7da7f60228a78de3710e7d4f27c3a8eb5
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 17 14:10:34 2022 +0300

    Doc fixes and small code fixes.

commit e3e5bc101641ceda429d8d98b1558dcc8aad5b0b
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 17 12:33:08 2022 +0300

    Updates to pma for portability.

commit c187096f20b78631fc991898e4db62c5d6a6a441
Merge: de7bb7ee 6b97a4f7
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Wed Jun 15 18:11:00 2022 +0300

    Merge branch 'master' into feature/pma2

commit de7bb7ee3e6d69c6c7985f43a0f06527f438e43d
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Wed Jun 15 14:16:07 2022 +0300

    Add cygwin case to m4/pma.m4.

commit d78e8b44f8b470d894b46a0ff4cafc88ce8eed29
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Tue Jun 14 22:43:52 2022 +0300

    Doc updates.

commit edc9ae773547c911d38b4a6fcb71946762df1e3d
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Tue Jun 14 22:40:58 2022 +0300

    Add Mac OS support to configuration machinery.

commit 37dbf039eee81652d647aa2783f4ea4cb0266f52
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Tue Jun 14 22:01:23 2022 +0300

    Add --disable-pma configure option and doc for it.

commit b0774ab145fe4828e54da22e6deb850fcceafcf4
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Tue Jun 14 15:13:38 2022 +0300

    Use -no-pie only for gcc and clang.

commit fdab60d8bd6d78159571d2c4e1c4d08e0684a0ab
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Mon Jun 13 22:59:00 2022 +0300

    Finish doc on persistent memory.

commit 17887261a7537f2e25f6cca63e1d67a93f3a3e36
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Mon Jun 13 13:41:19 2022 +0300

    Doc and code improvements.

commit 24184e361b734aff4c7c9e96b0090cfaaf351e2d
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 10 14:58:26 2022 +0300

    Fix for non-pma build.

commit f10f4af373c7ace425f2af9a68f5d6f4daa52bb3
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 10 14:54:54 2022 +0300

    Get persistent stuff working!

commit 920119080d877186165506ba819a548a5ea4ae85
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Jun 10 10:29:53 2022 +0300

    Attempt pma symbol table integration. Works in pass through mode.

commit 36ba3cb86acd0cf8b70d78391ef0b77279b57b7c
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Thu Jun 9 22:00:21 2022 +0300

    Add pma support, based on env var.

2 files changed, 73 insertions, 0 deletions

diff --git a/m4/ChangeLog b/m4/ChangeLog
index fb2467fb..aaac3b88 100644
--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,25 @@
+2022-06-15         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* pma.m4: Add case for Cygwin.
+
+2022-06-14         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* pma.m4: Put -no-pie inside additional check for gcc and clang.
+	Tinycc and PCC are no-PIE anyway.  Add support for --disable-pma.
+	Add the right magic for Mac OS.
+
+2022-06-13         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* pma.m4: Put -no-pie inside check for Linux.
+
+2022-06-10         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* pma.m4: Add -no-pie to LDFLAGS for persistent malloc.
+
+2022-06-09         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* pma.m4: New file.
+
 2021-10-27         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* 5.1.1: Release tar ball made.
diff --git a/m4/pma.m4 b/m4/pma.m4
new file mode 100644
index 00000000..f6f6e969
--- /dev/null
+++ b/m4/pma.m4
@@ -0,0 +1,51 @@
+dnl Decide whether or not to use the persistent memory allocator
+
+# Copyright (C) 2022 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([GAWK_USE_PERSISTENT_MALLOC],
+[
+use_persistent_malloc=no
+if test "$SKIP_PERSIST_MALLOC" = no
+then
+	AC_CHECK_FUNC([mmap])
+	AC_CHECK_FUNC([munmap])
+	if test $ac_cv_func_mmap = yes && test $ac_cv_func_munmap = yes
+	then
+		AC_DEFINE(USE_PERSISTENT_MALLOC, 1, [Define to 1 if we can use the pma allocator])
+		use_persistent_malloc=yes
+		case $host_os in
+		linux-*)
+			case $CC in
+			gcc | clang)
+				LDFLAGS="${LDFLAGS} -no-pie"
+				export LDFLAGS
+				;;
+			*)
+				# tinycc and pcc don't support -no-pie flag
+				# their executables are non-PIE automatically
+				# so no need to do anything
+				;;
+			esac
+			;;
+		*darwin*)
+			LDFLAGS="${LDFLAGS} -Xlinker -no_pie"
+			export LDFLAGS
+			;;
+		*cygwin* | *CYGWIN*)
+			true	# nothing do, Cygwin exes are not PIE
+			;;
+		# Other OS's go here...
+		*)
+			# For now, play it safe
+			use_persistent_malloc=no
+			;;
+		esac
+	else
+		use_persistent_malloc=no
+	fi
+fi
+AM_CONDITIONAL([USE_PERSISTENT_MALLOC], [test "$use_persistent_malloc" = "yes"])
+])