port install procmail fails with invalid implicit declaration on Big Sur

[pwosel]

% sudo port install procmail
--->  Fetching archive for procmail
--->  Attempting to fetch procmail-3.22_8.darwin_20.x86_64.tbz2 from https://packages.macports.org/procmail
--->  Attempting to fetch procmail-3.22_8.darwin_20.x86_64.tbz2 from https://nue.de.packages.macports.org/procmail
--->  Attempting to fetch procmail-3.22_8.darwin_20.x86_64.tbz2 from https://lil.fr.packages.macports.org/procmail
--->  Fetching distfiles for procmail
--->  Verifying checksums for procmail
--->  Extracting procmail
--->  Applying patches to procmail
--->  Configuring procmail
--->  Building procmail
Error: Failed to build procmail: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_mail_procmail/procmail/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port procmail failed


:info:build make[1]: Entering directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_mail_procmail/procmail/work/procm
ail-3.22/src'
:info:build /bin/sh ./autoconf /bin/sh "/bin/rm -f" "mv -f" /dev/null \
:info:build  "grep -F" "/Library/Developer/CommandLineTools/usr/bin/make" o "/tmp" \
:info:build  "/opt/local/bin" ../autoconf.h
:info:build Using the following directories for the LOCKINGTESTs:
:info:build   /tmp
:info:build Initiating fcntl()/kernel-locking-support tests
:info:build Whoeaaa!  There's something fishy going on here.
:info:build You have a look and see if you detect anything uncanny:
:info:build *******************************************************
:info:build make[2]: Entering directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_mail_procmail/procmail/work/procm
ail-3.22/src'
:info:build /usr/bin/clang -arch x86_64 -c -O   _autotst.c
:info:build In file included from _autotst.c:2:
:info:build ./../config.h:3:43: warning: '/*' within block comment [-Wcomment]
:info:build /*#define sMAILBOX_SEPARATOR    "\1\1\1\1\n"    /* sTART- and eNDing separ.  */
:info:build                                                 ^
:info:build ./../config.h:4:43: warning: '/*' within block comment [-Wcomment]
:info:build /*#define eMAILBOX_SEPARATOR    "\1\1\1\1\n"    /* uncomment (one or both)
:info:build                                                 ^
:info:build ./../config.h:49:28: warning: '/*' within block comment [-Wcomment]
:info:build /*#define GROUP_PER_USER                        /* uncomment this if each
:info:build                                                 ^
:info:build ./../config.h:55:20: warning: '/*' within block comment [-Wcomment]
:info:build /*#define LMTP                                  /* uncomment this if you
:info:build                                                 ^
:info:build ./../config.h:80:26: warning: '/*' within block comment [-Wcomment]
:info:build /*#define NO_fcntl_LOCK         /* uncomment any of these three if you       */
:info:build                                 ^
:info:build ./../config.h:81:26: warning: '/*' within block comment [-Wcomment]
:info:build /*#define NO_lockf_LOCK         /* definitely do not want procmail to make   */
:info:build                                 ^
:info:build ./../config.h:82:26: warning: '/*' within block comment [-Wcomment]
:info:build /*#define NO_flock_LOCK         /* use of those kernel-locking methods       */
:info:build                                 ^
:info:build ./../config.h:88:29: warning: '/*' within block comment [-Wcomment]
:info:build /*#define RESTRICT_EXEC 100     /* uncomment to prevent users with uids equal
:info:build                                 ^
:info:build ./../config.h:94:29: warning: '/*' within block comment [-Wcomment]
:info:build /*#define NO_NFS_ATIME_HACK     /* uncomment if you're definitely not using
:info:build                                 ^
:info:build ./../config.h:101:44: warning: '/*' within block comment [-Wcomment]
:info:build /*#define DEFsendmail   "/usr/sbin/sendmail"    /* uncomment and/or change if
:info:build                                                 ^
:info:build ./../config.h:129:34: warning: '/*' within block comment [-Wcomment]
:info:build /*#define console       "/dev/console"  /* uncomment if you want procmail to
:info:build                                         ^
:info:build _autotst.c:62:30: error: implicit declaration of function 'killchildren' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
:info:build { timeout=1;close(fdcollect);killchildren();
:info:build                              ^
:info:build _autotst.c:66:14: error: implicitly declaring library function 'exit' with type 'void (int) __attribute__((noreturn))' [-Werror,-Wimplicit-function-declaration]
:info:build { stimeout();exit(1);
:info:build              ^
:info:build _autotst.c:66:14: note: include the header <stdlib.h> or explicitly provide a declaration for 'exit'
:info:build _autotst.c:126:8: error: implicit declaration of function 'fdlock' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
:info:build               fdlock(goodlock);
:info:build               ^
:info:build _autotst.c:126:8: note: did you mean 'flock'?
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX11.0.sdk/usr/include/sys/fcntl.h:568:9: note: 'flock' declared here
:info:build int     flock(int, int);
:info:build         ^
:info:build _autotst.c:145:11: error: implicit declaration of function 'sfdlock' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
:info:build               if(sfdlock(fd))
:info:build                  ^
:info:build _autotst.c:145:11: note: did you mean 'flock'?
:info:build /Library/Developer/CommandLineTools/SDKs/MacOSX11.0.sdk/usr/include/sys/fcntl.h:568:9: note: 'flock' declared here
:info:build int     flock(int, int);
:info:build         ^
:info:build _autotst.c:152:11: error: implicit declaration of function 'fdunlock' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
:info:build               if(fdunlock()||close(fd))
:info:build                  ^
:info:build _autotst.c:167:13: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]
:info:build               if(fp=fopen("_locktst.pid","w"))
:info:build                  ~~^~~~~~~~~~~~~~~~~~~~~~~~~~
:info:build _autotst.c:167:13: note: place parentheses around the assignment to silence this warning
:info:build               if(fp=fopen("_locktst.pid","w"))
:info:build                    ^
:info:build                  (                           )
:info:build _autotst.c:167:13: note: use '==' to turn this assignment into an equality comparison
:info:build               if(fp=fopen("_locktst.pid","w"))
:info:build                    ^
:info:build                    ==
:info:build _autotst.c:184:31: error: implicit declaration of function 'killchildren' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
:info:build            alarm(0);close(fdcollect);killchildren();
:info:build                                      ^
:info:build _autotst.c:233:10: error: implicit declaration of function 'fdlock' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
:info:build   return fdlock(fd);
:info:build          ^
:info:build _autotst.c:236:8: warning: type specifier missing, defaults to 'int' [-Wimplicit-int]
:info:build static oldfdlock;
:info:build ~~~~~~ ^
:info:build 13 warnings and 7 errors generated.
:info:build make[2]: *** [_autotst.o] Error 1
:info:build make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_mail_procmail/procmail/work/procma