remove SHOPT_REGRESS (re: 506bd2b); tweak build system

SHOPT_REGRESS is the ksh compile-time option that enables
instrumented intercepts of system calls and the like. It was an
experiment that was quietly added in 93t+ 2009-04-15 and then
apparently forgotten about, as no change was ever made after that.

By 93u+ 2012-08-01 (which we forked), enabling it was crashing the
shell, which was fixed in commit 506bd2b, but it still doesn't
really work consistently: in my experiments with the associated
ksh-regress.rt regression tests, I noticed that the output varies
based on (a) the operating system, and (b) the presence of profile
scripts such as /etc/ksh.kshrc on the system. No one has time to
look into this further, so this commit removes that dead weight.

____
This commit also makes related tweaks to the build system:

The statically linked shell was crashing after removing regress.c,
because regress.o with its intercepts was still present in
libshell.a. To avoid similar in future, the code to link a static
library (currently repeated in five Mamfiles) is consolidated into
a new MAM include file, src/cmd/INIT/include/link_ar.mam, and
extended with code to remove object files whose sources are no
longer part of the code base. In addition, the 'ar' command usage
is updated to conform with the POSIX standard (options start with
a '-'), and the obsolete `ranlib` invocation is removed.

In mamake, the 'incl' command (added in 2757793) no longer
saves/clears and restores the automatic variables, as we need them
to work normally for link_ar.mam. They are now once again saved and
restored only when the 'bind' command includes a file.

src/cmd/INIT/README-mamake.md

@@ -43,6 +43,8 @@ the language to facilitate human maintenance of the `Mamfile`s.
         * [...while scanning and sorting leaf directories](#user-content-while-scanning-and-sorting-leaf-directories)
         * [...while building the current directory](#user-content-while-building-the-current-directory)
     * [Repeatedly iterating through a block](#user-content-repeatedly-iterating-through-a-block)
+    * [Including a MAM file](#user-content-including-a-mam-file)
+        * [Provided include files](#user-content-provided-include-files)
 * [Parallel processing](#user-content-parallel-processing)
 * [Debugging mamake](#user-content-debugging-mamake)
 * [Appendix: Main changes from the AT&T version](#user-content-appendix-main-changes-from-the-att-version)
@@ -502,8 +504,20 @@ iteration *variable*.
 `incl` *filename*
 
 The `incl` command reads a file with MAM commands from *filename* as if
-those commands had appeared in place of the `incl` command, except that the
-automatic variables are saved before and restored after reading.
+those commands had appeared in place of the `incl` command.
+If *filename* does not contain a `/`, mamake will look for the file in the
+current directory first, then in `%{PACKAGEROOT}/src/cmd/INIT/include`.
+
+#### Provided include files ####
+
+The following are provided in `%{PACKAGEROOT}/src/cmd/INIT/include`:
+
+* `link_ar.mam`: A shell action (see `exec` above) for linking a static
+  library archive (`lib`*name*`.a`) based on the contents of the automatic
+  variables, for including at the end of a `make lib`*name*`.a`...`done`
+  rule. All the child rules are expected to be `*.o` object files. The
+  action also deletes object files that no longer have a matching source
+  from the archive.
 
 ## Parallel processing ##
 

src/cmd/INIT/include/link_ar.mam

@@ -0,0 +1,34 @@
+note *	Shell action for linking an archive (static library) from previously
+note *	compiled object files, based on the current MAM automatic variables.
+note *
+note *	- %{@} - name of archive (like libfoo.a)
+note *	- %{^} - all the *.o files
+note *	- %{?} - the *.o files that changed in this run
+note *
+note *	This code avoids rebuilding the archive from scratch on each run,
+note *	updating only the object files that have changed.
+
+exec -	if	test -f %{@}
+exec -	then	ar -r -c %{@} %{?}  # add changed *.o
+exec -	else	ar -r -c %{@} %{^}  # add all *.o
+exec -	fi || exit
+
+note *	Sometimes, obsolete object files can interfere due to intercepts, so
+note *	delete any old object files that we no longer build from the archive
+
+exec -	to_delete=
+exec -	for o in $(ar -t %{@})
+exec -	do	case $o in
+exec -		*.o)	case ' %{^} ' in
+exec -			*" $o "*)
+exec -				;;
+exec -			*)	to_delete="${to_delete-} $o"
+exec -				;;
+exec -			esac
+exec -			;;
+exec -		esac
+exec -	done
+exec -	case ${to_delete:+y} in
+exec -	y)	ar -d %{@} $to_delete
+exec -		;;
+exec -	esac

src/cmd/INIT/mamake.c

@@ -28,7 +28,7 @@
  * coded for portability
  */
 
-#define RELEASE_DATE "2024-11-26"
+#define RELEASE_DATE "2024-12-03"
 static char id[] = "\n@(#)$Id: mamake (ksh 93u+m) " RELEASE_DATE " $\0\n";
 
 #if _PACKAGE_ast
@@ -1767,21 +1767,12 @@ static int include(Rule_t *r, Makestate_t *stp, char *file, int pushflags)
 	int	rv;
 	if (rv = push(file, NULL, pushflags))
 	{
-		/* save automatic variables */
-		char *s1 = auto_prev->value, *s2 = auto_allprev->value, *s3 = auto_updprev->value;
-		auto_prev->value = auto_allprev->value = auto_updprev->value = empty;
-		/* read the file */
 		report(-1, file, "include", NULL);
+		state.indent++;
 		make(r, stp);
+		state.indent--;
+		report(-1, file, "end of", NULL);
 		pop();
-		/* restore automatic variables */
-		if (auto_prev->value != empty)
-			free(auto_prev->value);
-		if (auto_allprev->value != empty)
-			free(auto_allprev->value);
-		if (auto_updprev->value != empty)
-			free(auto_updprev->value);
-		auto_prev->value = s1, auto_allprev->value = s2, auto_updprev->value = s3;
 	}
 	return rv;
 }
@@ -2167,6 +2158,7 @@ static void make(Rule_t *r, Makestate_t *parentstate)
 			}
 			if (s = require(t, !strcmp(v, "dontcare")))
 			{
+				char *s1, *s2, *s3;
 				char *libname = t + 2;
 				/*
 				 * bind to the *.a files that require() just derived from $INSTALLROOT/lib/lib/NAME
@@ -2216,10 +2208,22 @@ static void make(Rule_t *r, Makestate_t *parentstate)
 					continue;
 				}
 				/* otherwise, include the rules file if it exists */
+				/* save automatic variables */
+				s1 = auto_prev->value, s2 = auto_allprev->value, s3 = auto_updprev->value;
+				auto_prev->value = auto_allprev->value = auto_updprev->value = empty;
+				/* read the file */
 				append(buf, state.installroot);
 				append(buf, "/lib/mam/");
 				append(buf, libname);
 				include(r, &st, use(buf), 0);
+				/* restore automatic variables */
+				if (auto_prev->value != empty)
+					free(auto_prev->value);
+				if (auto_allprev->value != empty)
+					free(auto_allprev->value);
+				if (auto_updprev->value != empty)
+					free(auto_updprev->value);
+				auto_prev->value = s1, auto_allprev->value = s2, auto_updprev->value = s3;
 			}
 			continue;
 
@@ -2307,6 +2311,15 @@ static void make(Rule_t *r, Makestate_t *parentstate)
 		case KEY('i','n','c','l'):
 			if (!*t || *v)
 				error_out("syntax error", u);
+			if (!strchr(t,'/'))
+			{
+				if (include(r, &st, t, 0))
+					continue;
+				append(buf, state.packageroot);
+				append(buf, "/src/cmd/INIT/include/");
+				append(buf, t);
+				t = use(buf);
+			}
 			include(r, &st, t, STREAM_MUST);
 			continue;
 

src/cmd/ksh93/Mamfile

@@ -223,14 +223,10 @@ make install virtual
 		prev %{INCLUDE_AST}/option.h
 	done
 
-	make include/regress.h
-	done
-
 	make include/argnod.h
 	done
 
 	make include/defs.h
-		prev include/regress.h
 		prev include/shtable.h
 		prev include/shell.h
 		prev %{INCLUDE_AST}/endian.h
@@ -657,16 +653,6 @@ make install virtual
 			prev shopt.h
 		done
 
-		make bltins/regress.c
-			prev %{INCLUDE_AST}/tmx.h
-			prev include/builtins.h
-			prev include/io.h
-			prev %{INCLUDE_AST}/ls.h
-			prev %{INCLUDE_AST}/error.h
-			prev include/defs.h
-			prev shopt.h
-		done
-
 		make sh/fault.c
 			prev include/ulimit.h
 			prev include/builtins.h
@@ -1070,14 +1056,8 @@ make install virtual
 			exec - %{compile} %{<}
 		done
 
-		note *
-		note * Link the library
-		note *
-		exec - if	test -f %{@}
-		exec - then	%{AR} rc %{@} %{?}  # add changed *.o
-		exec - else	%{AR} rc %{@} %{^}  # add all *.o
-		exec - fi || exit
-		exec - ranlib %{@} >/dev/null 2>&1 || true
+		note * include shell action for linking the library
+		incl link_ar.mam
 
 		note * save for dylink
 		setv _libshell_object_files_ %{^}

src/cmd/ksh93/README

@@ -128,9 +128,6 @@ The options have the following defaults and meanings:
     P_SUID       0   If set, all real UIDs greater than or equal to this value
                      will require the -p option to run the shell setuid/setgid.
 
-    REGRESS      off Enable the __regress__ built-in command and instrumented
-                     intercepts for testing.
-
     REMOTE       off Set --rc (read profile scripts) even if ksh was invoked
                      with standard input on a socket, i.e. as a remote shell.
 

src/cmd/ksh93/SHOPT.sh

@@ -31,7 +31,6 @@ SHOPT NOECHOE=0				# turn off 'echo -e' when SHOPT_ECHOPRINT is disabled
 SHOPT OPTIMIZE=1			# optimize loop invariants
 SHOPT P_SUID=0				# real UIDs >= this value require -p for set[ug]id (to turn off, use empty, not 0)
 SHOPT PRINTF_LEGACY=			# allow noncompliant printf(1) syntax (format arg starting with '-' without prior '--')
-SHOPT REGRESS=				# enable __regress__ builtin and instrumented intercepts for testing
 SHOPT REMOTE=				# enable --rc if running as a remote shell
 SHOPT SCRIPTONLY=0			# build ksh for running scripts only; compile out the interactive shell
 SHOPT SPAWN=				# use spawnveg for fork/exec