Moved error() to a library and wrote a Makefile.

Makefile

@@ -0,0 +1,50 @@
+# Copyright (c) 2022-2023 Luiz Antônio Rangel <[email protected]>
+# SPDX-Licence-Identifier: BSD-2-Clause
+
+# Paths
+ROOT ?=
+DEFUSRBIN ?= /usr/bin/
+DEFSBIN ?= /sbin/
+MANDIR ?= /usr/share/man/
+STATIC_LIBDIR ?= /usr/lib/
+SYSINCLUDE_DIR ?= /usr/include/sys/
+INCLUDE_DIR ?= /usr/include/
+
+# Programs
+CC ?= gcc
+LD ?= ld
+AR ?= ar
+INSTALL ?= /bin/install
+
+all: libegacy-compat test-libegacy-compat \
+	src/cdefs.h src/error.h src/queue.h src/tree.h
+
+# Only error() and error_at_line() available for now.
+libegacy-compat: error.o
+	$(AR) r libegacy-compat.a error.o
+
+error.o: src/error.c src/error.h
+	$(CC) -I src/ -c ./src/error.c -o error.o
+
+install: install-sysheaders install-headers install-libegacy-compat
+
+install-sysheaders: src/cdefs.h src/queue.h src/tree.h
+	for sys_header in src/cdefs.h src/queue.h src/tree.h; do \
+		$(INSTALL) -c -m 644 $$sys_header $(ROOT)$(SYSINCLUDE_DIR) ; \
+	done
+
+install-headers: src/error.h
+	for header in src/error.h; do \
+		$(INSTALL) -c -m 644 $$header $(ROOT)$(INCLUDE_DIR) ; \
+	done
+
+install-libegacy-compat: install-headers libegacy-compat
+	$(INSTALL) -c -m 664 ./libegacy-compat.a $(ROOT)$(STATIC_LIBDIR)
+
+test-libegacy-compat: libegacy-compat tests/error_at_line_test.c
+	$(CC) tests/error_at_line_test.c -Isrc/ -L. -legacy-compat
+	./a.out
+	@echo 'The '\''error_at_line()'\'' function of libegacy-compat is working.'
+
+clean:
+	rm -f a.out *.o *.a *~ 

README.md

@@ -1,13 +1,47 @@
 # musl-compat
 Legacy compatibility headers for the musl libc.
 
-## Who's the responsible?
-All kudos for the C language source code goes to the NetBSD and OpenBSD
-team — read the copyright header of each file for more information.  
+## Build and install
 
-All kudos for the original packaging (in fact, taking these headers,
-testing it etc) goes to the Void Linux team.  
+If you wish to install everything, you can use the following:
 
-And, for last but not least, the `do_install.ksh` script was made
-entirely by me, so if you have any problems related specifically to
-the script, blame it on me. :^)
+```console
+gmake && gmake install
+```
+
+If you wish to install just the system headers, you can use:
+
+```console
+gmake install-sysheaders
+```
+
+And, if you wish to just install the ``error.h`` header along with the library
+containing its functions, you can go with:
+
+```console
+gmake && gmake test-libegacy-compat \
+    && gmake install-libegacy-compat
+```
+
+That's pretty much about it.
+
+## How can I use the "libegacy-compat"?
+
+In your ``LDFLAGS``, add the value of ``-legacy-compat``.
+Yeah, simple as that.
+
+## Licence
+
+``error.h`` and ``error.c``, part of ``libegacy-compat``, are covered by the
+[BSD 2-Clause licence](./LICENCE), along with the Makefile itself.
+Maybe this library can be updated and more compatibility functions be added
+along the time, but there's no guarantee of that for now.
+
+``sys/tree.h`` was copied verbatim from the NetBSD source-tree by the Void Linux
+project, so it's covered by the BSD 2-Clause licence too.  
+``sys/queue.h`` was also copied from NetBSD, but it's covered by the BSD 3-Clause
+licence and its ownership is claimed by The Regents of the University of California.
+
+The test of ``error_at_line``(3) was taken from GNU m4 1.4.18 configure
+Shell script, so it's covered --- or better, not covered --- by the
+[FSF Unlimited License](./tests/LICENCE.FSFUL).

src/error.c

@@ -0,0 +1,63 @@
+// Copyright (C) 2015 - 2022 Void Linux contributors
+// Copyright (C) 2023 Pindorama
+// 		      Luiz Antônio Rangel 
+// SPDX-Licence-Identifier: BSD-2-Clause
+
+#include "error.h"
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+// The calling program shall set "program_invocation_name" to the name of the
+// executing program itself.
+extern char *program_invocation_name;
+// Documented at the "error.h" header.
+extern unsigned int error_message_count = 0;
+extern int error_one_per_line = 0;
+
+extern void error(int status, int errnum, const char* format, ...)
+{
+	// Should be fflush(stdout), but that's unspecified if stdout has been closed;
+	// stick with fflush(NULL) for simplicity (GNU C library checks if the
+	// file descriptor is still valid).
+	fflush(NULL);
+
+	va_list ap;
+	fprintf(stderr, "%s: ", program_invocation_name);
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+	if (errnum)
+		fprintf(stderr, ": %s", strerror(errnum));
+	fprintf(stderr, "\n");
+	error_message_count++;
+	if (status)
+		exit(status);
+}
+
+
+extern void error_at_line(int status, int errnum, const char *filename,
+		unsigned int linenum, const char *format, ...)
+{
+	va_list ap;
+	if (error_one_per_line) {
+		static const char *old_filename;
+		static int old_linenum;
+		if (linenum == old_linenum && filename == old_filename)
+			return;
+		old_filename = filename;
+		old_linenum = linenum;
+	}
+	fprintf(stderr, "%s: %s:%u: ", program_invocation_name, filename, linenum);
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+	if (errnum)
+		fprintf(stderr, ": %s", strerror(errnum));
+	fprintf(stderr, "\n");
+	error_message_count++;
+	if (status)
+		exit(status);
+}

src/error.h

@@ -1,60 +1,24 @@
-#ifndef _ERROR_H_
-#define _ERROR_H_
-
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-
-#warning usage of non-standard #include <error.h> is deprecated
+// Copyright (C) 2015 - 2022 Void Linux contributors
+// Copyright (C) 2023 Pindorama
+// 		      Luiz Antônio Rangel 
+// SPDX-Licence-Identifier: BSD-2-Clause
 
-static unsigned int error_message_count = 0;
+#if !defined(_ERROR_H_)
+#define _ERROR_H_
 
-static inline void error(int status, int errnum, const char* format, ...)
-{
-	/* should be fflush(stdout), but that's unspecified if stdout has been closed;
-	 * stick with fflush(NULL) for simplicity (glibc checks if the fd is still valid) */
-	fflush(NULL);
+#warning usage of non-standard `#include <error.h>' is deprecated
 
-	va_list ap;
-	fprintf(stderr, "%s: ", program_invocation_name);
-	va_start(ap, format);
-	vfprintf(stderr, format, ap);
-	va_end(ap);
-	if (errnum)
-		fprintf(stderr, ": %s", strerror(errnum));
-	fprintf(stderr, "\n");
-	error_message_count++;
-	if (status)
-		exit(status);
-}
+// As it suggests, it counts how many times error() was called, by being
+// incremented every call.
+static unsigned int error_message_count;
 
-static int error_one_per_line = 0;
+// If this is set non-zero, a sequence of error_at_line(3) calls with the
+// same *filename and linenum values as input will result in only one entry
+// on the specified file.
+static int error_one_per_line;
 
+static inline void error(int status, int errnum, const char* format, ...);
 static inline void error_at_line(int status, int errnum, const char *filename,
-		unsigned int linenum, const char *format, ...)
-{
-	va_list ap;
-	if (error_one_per_line) {
-		static const char *old_filename;
-		static int old_linenum;
-		if (linenum == old_linenum && filename == old_filename)
-			return;
-		old_filename = filename;
-		old_linenum = linenum;
-	}
-	fprintf(stderr, "%s: %s:%u: ", program_invocation_name, filename, linenum);
-	va_start(ap, format);
-	vfprintf(stderr, format, ap);
-	va_end(ap);
-	if (errnum)
-		fprintf(stderr, ": %s", strerror(errnum));
-	fprintf(stderr, "\n");
-	error_message_count++;
-	if (status)
-		exit(status);
-}
-
+		unsigned int linenum, const char *format, ...);
 
 #endif	/* _ERROR_H_ */

src/queue.h

@@ -4,29 +4,7 @@
  * Copyright (c) 1991, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
+ * SPDX-Licence-Identifier: BSD-3-Clause
  *
  *	@(#)queue.h	8.5 (Berkeley) 8/20/94
  */

src/tree.h

@@ -4,25 +4,8 @@
  * Copyright 2002 Niels Provos <[email protected]>
  * All rights reserved.
  *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
+ * SPDX-Licence-Identifier: BSD-2-Clause
  *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef	_SYS_TREE_H_

tests/LICENCE.FSFUL

@@ -0,0 +1,5 @@
+Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
+
+
+This configure script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it.

tests/error_at_line_test.c

@@ -0,0 +1,13 @@
+// Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
+// From GNU m4 1.4.18 configure Shell script.
+// 
+// SPDX-Licence-Identifier: FSFUL
+
+#include <error.h>
+int
+main ()
+{
+error_at_line (0, 0, "", 0, "an error occurred");
+  ;
+  return 0;
+}