Update, rename and clean up various scripts

Rename contrib/tools/chkfmt to contrib/tools/chkfmt.sh; refactor:
 * Increase the max line length for contrib/**/*.[ch] from 96 to 100.
 * Set the max line length for ci_*.sh to 100.
 * Use `basename $0` instead of the hard-coded script name.
 * Update comments.

Remove contrib/tools/reindent. For automated code formatting, including
indentation, we need a robust solution.

Add an empty line after the hashbang line in all scripts.

Remove the "last changed" version info from comment headers.
(The version control system maintains this information automatically.)

7 files changed, 46 insertions, 63 deletions

diff --git a/contrib/testpngs/makepngs.sh b/contrib/testpngs/makepngs.sh
index eb1c15fc9..270f0630a 100755
--- a/contrib/testpngs/makepngs.sh
+++ b/contrib/testpngs/makepngs.sh
@@ -1,12 +1,10 @@
 #!/bin/sh
-#
+
 # Make a set of test PNG files, MAKEPNG is the name of the makepng executable
 # built from contrib/libtests/makepng.c
 
 # Copyright (c) 2015 John Cunningham Bowler
 
-# Last changed in libpng 1.6.20 [December 3, 2015]
-
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h
diff --git a/contrib/tools/chkfmt b/contrib/tools/chkfmt.sh
index 95181fde2..8810aa7b5 100755
--- a/contrib/tools/chkfmt
+++ b/contrib/tools/chkfmt.sh
@@ -1,21 +1,28 @@
 #!/bin/sh
 
-# chkfmt
+# chkfmt.sh
 #
-# COPYRIGHT: Written by John Cunningham Bowler, 2010.
+# COPYRIGHT:
+# Written by John Cunningham Bowler, 2010.
+# Revised by Cosmin Truta, 2022.
 # To the extent possible under law, the author has waived all copyright and
-# related or neighboring rights to this work.  This work is published from:
-# United States.
+# related or neighboring rights to this work.  The author published this work
+# from the United States.
 #
-# Check the format of the source files in the current directory - checks for a
-# line length of 80 characters max and no tab characters.
+# Check the format of the source files in the current directory:
+#
+#  * The lines should not exceed a predefined maximum length.
+#  * Tab characters should appear only where necessary (e.g. in makefiles).
 #
 # Optionally arguments are files or directories to check.
 #
-# -v: output the long lines (makes fixing them easier)
-# -e: spawn an editor for each file that needs a change ($EDITOR must be
-#     defined).  When using -e the script MUST be run from an interactive
-#     command line.
+#  -v: output the long lines (makes fixing them easier)
+#  -e: spawn an editor for each file that needs a change ($EDITOR must be
+#      defined).  When using -e the script MUST be run from an interactive
+#      command line.
+
+script_name=`basename "$0"`
+
 verbose=
 edit=
 vers=
@@ -32,14 +39,14 @@ test "$1" = "-e" && {
       # Copy the standard streams for the editor
       exec 3>&0 4>&1 5>&2
    else
-      echo "chkfmt -e: EDITOR must be defined" >&2
+      echo "$script_name -e: EDITOR must be defined" >&2
       exit 1
    fi
 }
 
 # Function to edit a single file - if the file isn't changed ask the user
-# whether or not to continue.  This stuff only works if the script is run from
-# the command line (otherwise, don't specify -e or you will be sorry).
+# whether or not to continue.  This stuff only works if the script is run
+# from the command line (otherwise, don't specify -e or you will be sorry).
 doed(){
    cp "$file" "$file".orig
    "$EDITOR" "$file" 0>&3 1>&4 2>&5 3>&- 4>&- 5>&- || exit 1
@@ -53,19 +60,22 @@ doed(){
    return 0
 }
 
-# In beta versions the version string which appears in files can be a little
-# long and cause spuriously overlong lines.  To avoid this substitute the version
-# string with a 'standard' version a.b.cc before checking for long lines.
+# In beta versions, the version string which appears in files can be a little
+# long and cause spuriously overlong lines.  To avoid this, substitute the
+# version string with a placeholder string "a.b.cc" before checking for long
+# lines.
+# (Starting from libpng version 1.6.36, we switched to a conventional Git
+# workflow, and we are no longer publishing beta versions.)
 if test -r png.h
 then
    vers="`sed -n -e \
    's/^#define PNG_LIBPNG_VER_STRING .\([0-9]\.[0-9]\.[0-9][0-9a-z]*\).$/\1/p' \
    png.h`"
-   echo "chkfmt: checking version $vers"
+   echo "$script_name: checking version $vers"
 fi
 if test -z "$vers"
 then
-   echo "chkfmt: png.h not found, ignoring version number" >&2
+   echo "$script_name: png.h not found, ignoring version number" >&2
 fi
 
 test -n "$1" || set -- .
@@ -89,13 +99,16 @@ find "$@" \( -type d \( -name '.git' -o -name '.libs' -o -name 'projects' \) \
          check_tabs=
          line_length=100;;
       *.awk)
-         # Includes literal tabs
+         # Allow literal tabs.
          check_tabs=
-         # The following is arbitrary
+         # Mainframe line printer, anyone?
          line_length=132;;
+      */ci_*.sh)
+         check_tabs=yes
+         line_length=100;;
       *contrib/*/*.[ch])
          check_tabs=yes
-         line_length=96;;
+         line_length=100;;
       *)
          check_tabs=yes
          line_length=80;;
diff --git a/contrib/tools/intgamma.sh b/contrib/tools/intgamma.sh
index 41c5d6dd2..3198cb241 100755
--- a/contrib/tools/intgamma.sh
+++ b/contrib/tools/intgamma.sh
@@ -1,13 +1,11 @@
 #!/bin/sh
-#
+
 # intgamma.sh
 #
-# Last changed in libpng 1.6.0 [February 14, 2013]
-#
 # COPYRIGHT: Written by John Cunningham Bowler, 2013.
 # To the extent possible under law, the author has waived all copyright and
-# related or neighboring rights to this work.  This work is published from:
-# United States.
+# related or neighboring rights to this work.  The author published this work
+# from the United States.
 #
 # Shell script to generate png.c 8-bit and 16-bit log tables (see the code in
 # png.c for details).
@@ -17,10 +15,10 @@
 # (0..255) value and a similar table for the exponent calculation.
 #
 # "bc" must be on the path when the script is executed, and the math library
-# (-lm) must be available
-#
-# function to print out a list of numbers as integers; the function truncates
-# the integers which must be one-per-line
+# (-lm) must be available.
+
+# Function to print out a list of numbers as integers; the function truncates
+# the integers which must be one-per-line.
 function print(){
    awk 'BEGIN{
       str = ""
diff --git a/contrib/tools/reindent b/contrib/tools/reindent
deleted file mode 100755
index f4df309b6..000000000
--- a/contrib/tools/reindent
+++ /dev/null
@@ -1,25 +0,0 @@
-#!/bin/sh
-
-# reindent a libpng C source
-
-# COPYRIGHT: Written by Glenn Randers-Pehrson, 2016.
-# To the extent possible under law, the author has waived all copyright and
-# related or neighboring rights to this work.  This work is published from:
-# United States.
-
-# Usage:
-# reindent inputtabsize outputtabsize inputcontinuestring outputcontinuestring
-#
-# Assumes that continued lines begin with indentation plus one space, and
-# that continued comments begin with indentation plus " *".
-#
-# eg, to change libpng coding style from 3-space indentation with 4-space
-# continuations to 4-space indentation with 2-space continuations:
-#
-#  reindent 3 4 "\t " "  " < example.c > example.c_4_2
-# and to restore the file back to libpng coding style
-#  reindent 4 3 "  " "    " < example.c_4_2 > example.c_3_4
-
-unexpand --first-only --t $1 | \
-   sed -e "/^	*$3[^\*]/{s/$3/$4/}" | \
-   expand -t $2
diff --git a/scripts/checksym.awk b/scripts/checksym.awk
index fe3af55e0..48e55e60e 100755
--- a/scripts/checksym.awk
+++ b/scripts/checksym.awk
@@ -1,4 +1,5 @@
 #!/bin/awk -f
+
 # Check a list of symbols against the master definition
 # (official) list.  Arguments:
 #
diff --git a/scripts/dfn.awk b/scripts/dfn.awk
index 0dc99df0f..0b25c8a37 100755
--- a/scripts/dfn.awk
+++ b/scripts/dfn.awk
@@ -1,8 +1,7 @@
 #!/bin/awk -f
+
 # scripts/dfn.awk - process a .dfn file
 #
-# last changed in libpng version 1.5.19 - August 21, 2014
-#
 # Copyright (c) 2013-2014 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
diff --git a/scripts/options.awk b/scripts/options.awk
index fef5dfd78..284811967 100755
--- a/scripts/options.awk
+++ b/scripts/options.awk
@@ -1,8 +1,7 @@
 #!/bin/awk -f
+
 # scripts/options.awk - library build configuration control
 #
-# last changed in libpng version 1.6.11 - June 5, 2014
-#
 # Copyright (c) 1998-2014 Glenn Randers-Pehrson
 #
 # This code is released under the libpng license.
@@ -243,7 +242,7 @@ $1 == "file" && NF >= 2{
 
 # option NAME ( (requires|enables|if) NAME* | on | off | disabled |
 #                sets SETTING VALUE+ )*
-#     
+#
 #   Declares an option 'NAME' and describes its default setting (disabled)
 #   and its relationship to other options.  The option is disabled
 #   unless *all* the options listed after 'requires' are set and at