Corner case: MacOS build fails if sh doesn't understand $(...)

[mjreed-wbd]

This is a bug report for perl from markjreed@gmail.com,
generated with the help of perlbug 1.42 running under perl 5.32.0.

---

[Please describe your issue here]
On one of my Macs I have installed the Heirloom Bourne shell,
used to check script compatibility with ancient versions of sh.
So when someone - be it plenv's perl-install, or me manually
following the usual instructions - runs sh ./Configure, it
blows up on the darwin hints file

./Configure: syntax error at line 346: `prodvers_minor=$' unexpected

That's actually line 346 of hints/darwin.sh:

prodvers_minor=$(echo $prodvers|awk -F. '{print $2}')

because the Heirloom shell doesn't understand the by-now
35-year-old "new" ksh/POSIX command-substitution syntax $(...).

I know that compatibility with really old UNIXes is not a priority,
and I may have the only system that is running both MacOS and
such an old version of sh. But the original Configure had a lot of
effort put into maintaing compatibility with just about everything,
and this is the only piece that doesn't work under Heirloom.; all
the other command substitutions use backticks. So It
Would Be Nice to fix it.

[Please do not change anything below this line]

---

Flags:
category=install
severity=low

Site configuration information for perl 5.32.0:

Configured by brew at Mon Jun 22 21:54:31 BST 2020.

Summary of my perl5 (revision 5 version 32 subversion 0) configuration:

Platform:
osname=darwin
osvers=19.5.0
archname=darwin-thread-multi-2level
uname='darwin catalina 19.5.0 darwin kernel version 19.5.0: tue may 26 20:41:44 pdt 2020; root:xnu-6153.121.2~2release_x86_64 x86_64 '
config_args='-des -Dprefix=/usr/local/Cellar/perl/5.32.0 -Dprivlib=/usr/local/Cellar/perl/5.32.0/lib/perl5/5.32.0 -Dsitelib=/usr/local/Cellar/perl/5.32.0/lib/perl5/site_perl/5.32.0 -Dotherlibdirs=/usr/local/lib/perl5/site_perl/5.32.0 -Dperlpath=/usr/local/opt/perl/bin/perl -Dstartperl=#!/usr/local/opt/perl/bin/perl -Dman1dir=/usr/local/Cellar/perl/5.32.0/share/man/man1 -Dman3dir=/usr/local/Cellar/perl/5.32.0/share/man/man3 -Duseshrplib -Duselargefiles -Dusethreads -Dsed=/usr/bin/sed'
hint=recommended
useposix=true
d_sigaction=define
useithreads=define
usemultiplicity=define
use64bitint=define
use64bitall=define
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
bincompat5005=undef
Compiler:
cc='cc'
ccflags ='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.15 -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -DPERL_USE_SAFE_PUTENV'
optimize='-O3'
cppflags='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.15 -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
ccversion=''
gccversion='4.2.1 Compatible Apple LLVM 11.0.3 (clang-1103.0.32.62)'
gccosandvers=''
intsize=4
longsize=8
ptrsize=8
doublesize=8
byteorder=12345678
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=16
longdblkind=3
ivtype='long'
ivsize=8
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries:
ld='cc'
ldflags =' -mmacosx-version-min=10.15 -fstack-protector-strong -L/usr/local/lib'
libpth=/usr/local/lib /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/lib /Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/lib /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib /usr/lib
libs=-lpthread -ldbm -ldl -lm -lutil -lc
perllibs=-lpthread -ldl -lm -lutil -lc
libc=
so=dylib
useshrplib=true
libperl=libperl.dylib
gnulibc_version=''
Dynamic Linking:
dlsrc=dl_dlopen.xs
dlext=bundle
d_dlsymun=undef
ccdlflags=' '
cccdlflags=' '
lddlflags=' -mmacosx-version-min=10.15 -bundle -undefined dynamic_lookup -L/usr/local/lib -fstack-protector-strong'

---

@inc for perl 5.32.0:
/usr/local/Cellar/perl/5.32.0/lib/perl5/site_perl/5.32.0/darwin-thread-multi-2level
/usr/local/Cellar/perl/5.32.0/lib/perl5/site_perl/5.32.0
/usr/local/Cellar/perl/5.32.0/lib/perl5/5.32.0/darwin-thread-multi-2level
/usr/local/Cellar/perl/5.32.0/lib/perl5/5.32.0
/usr/local/lib/perl5/site_perl/5.32.0/darwin-thread-multi-2level
/usr/local/lib/perl5/site_perl/5.32.0

---

Environment for perl 5.32.0:
DYLD_LIBRARY_PATH (unset)
HOME=/Users/mjreed
LANG=en_US.UTF-8
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/share/dotnet:/opt/X11/bin
PERL_BADLANG (unset)
SHELL=/bin/zsh

[Tux]

Does

prodvers_minor=`echo $prodvers | awk -F. '{print $2}'`

work for you?