manibuilder: Refresh DJGPP image

Replace the unmaintained anibali/djgpp image with a Debian-based image
that installs the current prebuilt DJGPP GCC 12.2.0 toolchain.

The old container depended on flashprog.org artifact downloads for a
pciutils patch and libgetopt tarball. Those URLs are gone, so build
against pciutils 3.15.0 directly and use the public getopt 2.5 tarball.

Update the manibuilder DJGPP tag and build documentation accordingly.

Tested:
- podman run ... getopt configure && make
- make -C util/manibuilder show-working
- make -C util/manibuilder -n 'djgpp:12.2.0-build'

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: If39a15012dc83b1a2b33e0824b1c44646a6a6964
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/520
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/README.md b/README.md
index 2051810..29d90e4 100644
--- a/README.md
+++ b/README.md
@@ -134,21 +134,28 @@
  in one subdirectory. There will be an extra subdirectory libpci-libgetopt
  created, which will contain compiled libpci and libgetopt.
 
- Download pciutils 3.5.6 and apply https://flashprog.org/wiki/File:Pciutils-3.5.6.patch.gz
- Compile pciutils, using following command line:
+ Download pciutils 3.15.0 and compile it using following command line:
 
     make ZLIB=no DNS=no HOST=i386-djgpp-djgpp CROSS_COMPILE=i586-pc-msdosdjgpp- \
-      PREFIX=/ DESTDIR=$PWD/../libpci-libgetopt  \
-      STRIP="--strip-program=i586-pc-msdosdjgpp-strip -s" install install-lib
+      PREFIX=/ DESTDIR=$PWD/../libpci-libgetopt install-lib
 
- Download and compile with 'make' https://flashprog.org/wiki/File:Libgetopt.tar.gz
+ Download getopt 2.5 from ftp.math.utah.edu and build the static library:
+
+    tar xzf getopt-2.5.tar.gz
+    cd getopt-2.5
+    printf '%s\n' 'char *gettext(const char *msgid);' >posix/gettext.h
+    sed -i -e 's,env/[gs]etenv\.c,,g' Makefile.in
+    AR=i586-pc-msdosdjgpp-ar RANLIB=i586-pc-msdosdjgpp-ranlib \
+      ./configure --host i586-pc-msdosdjgpp
+    make
 
  Copy the libgetopt.a to ../libpci-libgetopt/lib and
- getopt.h to ../libpci-libgetopt/include
+ posix/getopt.h to ../libpci-libgetopt/include
 
  Enter the flashprog directory.
 
-   make CC=i586-pc-msdosdjgpp-gcc STRIP=i586-pc-msdosdjgpp-strip \
+   make CC=i586-pc-msdosdjgpp-gcc AR=i586-pc-msdosdjgpp-ar \
+     RANLIB=i586-pc-msdosdjgpp-ranlib STRIP=i586-pc-msdosdjgpp-strip \
      LIBS_BASE=../libpci-libgetopt/ HAS_LIBPCI=yes CONFIG_LIBPCI_LDFLAGS=-lpci \
      strip