mamake: unified function for including files (re: f58153d)

Mamfiles currently include other files with MAM code upon 'setv CC'
to read the compiler probe results from lib/probe/C/mam/HASHEDPATH,
and upon 'bind -lfoo' to read the dependency rules for libfoo from
lib/mam/foo.

To ensure current and future consistency, this commit consolidates
the include functionality in an include() function that also saves
and restores the automatic variables.

This functionality is now also exposed to the MAM language in the
form of a new 'incl' command. It's currently unused, but may come
in handy one day, and it's so trivial it seems silly not to add it.

src/cmd/INIT/README-mamake.md

@@ -497,6 +497,14 @@ iteration *variable*.
 
 `loop` requires that the Mamfile be seekable (i.e.: not a pipe).
 
+### Including a MAM file ###
+
+`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.
+
 ## Parallel processing ##
 
 As of strict level 5, `mamake` supports parallel building using the new

src/cmd/INIT/mamake.c

@@ -28,7 +28,7 @@
  * coded for portability
  */
 
-#define RELEASE_DATE "2024-11-23"
+#define RELEASE_DATE "2024-11-26"
 static char id[] = "\n@(#)$Id: mamake (ksh 93u+m) " RELEASE_DATE " $\0\n";
 
 #if _PACKAGE_ast
@@ -1758,6 +1758,34 @@ static void run(Rule_t *r, char *s)
 	drop(buf);
 }
 
+/*
+ * include file in rule r
+ */
+
+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);
+		make(r, stp);
+		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;
+}
+
 /*
  * generate (if necessary) and read the MAM probe information
  * done on the first `setv CC ...'
@@ -1803,7 +1831,7 @@ static void probe(Rule_t *r, Makestate_t *stp)
 	s = use(buf);
 	/* generate probe info if it is nonexistent or older than mamprobe */
 	output_time = stat(s, &st) ? 0 : st.st_mtime;
-	if (output_time < cmd_time || !push(s, NULL, 0))
+	if (output_time < cmd_time || !include(r, stp, s, 0))
 	{
 		Buf_t	*tmp = buffer();
 		append(tmp, cmd);
@@ -1814,13 +1842,10 @@ static void probe(Rule_t *r, Makestate_t *stp)
 		if (execute(NULL, use(tmp)))
 			error_out("cannot generate probe info", s);
 		drop(tmp);
-		if (!push(s, NULL, 0))
-			error_out("cannot read probe info", s);
+		include(r, stp, s, STREAM_MUST);
 	}
 	free(cmd);
 	drop(buf);
-	make(r, stp);
-	pop();
 }
 
 /*
@@ -2194,22 +2219,7 @@ static void make(Rule_t *r, Makestate_t *parentstate)
 				append(buf, state.installroot);
 				append(buf, "/lib/mam/");
 				append(buf, libname);
-				s = use(buf);
-				if (push(s, NULL, 0))
-				{
-					char *s1 = auto_prev->value, *s2 = auto_allprev->value, *s3 = auto_updprev->value;
-					auto_prev->value = auto_allprev->value = auto_updprev->value = empty;
-					report(-1, s, "bind: include", NULL);
-					make(r, &st);
-					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;
-					pop();
-				}
+				include(r, &st, use(buf), 0);
 			}
 			continue;
 
@@ -2294,6 +2304,12 @@ static void make(Rule_t *r, Makestate_t *parentstate)
 			}
 			continue;
 
+		case KEY('i','n','c','l'):
+			if (!*t || *v)
+				error_out("syntax error", u);
+			include(r, &st, t, STREAM_MUST);
+			continue;
+
 		case KEY('l','o','o','p'):
 		{
 			off_t		saveoff;