--- a/src/configuration.c	2021-06-29 17:44:20.481179981 +0200
+++ b/src/configuration.c	2021-06-29 17:44:52.580655950 +0200
@@ -37,21 +37,12 @@
  * Preprocessor concatenation that expands preprocessor tokens as
  * needed by leveraging the usual indirection technique.
  */
-///@{
-/// Underlying string concatenation macro.
-#define MPTCPD_CONCAT_IMPL(x, ...) x ## __VA_ARGS__
-
-/// Concatenate strings using the preprocessor.
-#define MPTCPD_CONCAT(x, ...) MPTCPD_CONCAT_IMPL(x, __VA_ARGS__)
-///@}
 
 // Compile-time default logging choice
 #ifndef MPTCPD_LOGGER
 // This should never occur!
 # error Problem configuring default log message destination.
 #endif
-/// Name of the default logging function determined at compile-time.
-#define MPTCPD_SET_LOG_FUNCTION MPTCPD_CONCAT(l_log_set_, MPTCPD_LOGGER)
 
 /**
  * @brief Get the function that sets the log message destination.
@@ -474,7 +465,6 @@
 
 struct mptcpd_config *mptcpd_config_create(int argc, char *argv[])
 {
-        MPTCPD_SET_LOG_FUNCTION();  // For early logging.
 
         struct mptcpd_config *const config =
                 l_new(struct mptcpd_config, 1);
--- a/src/mptcpize.c	2021-06-29 19:29:57.810281053 +0200
+++ b/src/mptcpize.c	2021-06-29 19:29:29.942701557 +0200
@@ -17,7 +17,6 @@
 #include <argp.h>
 #include <dlfcn.h>
 #include <errno.h>
-#include <error.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -79,7 +78,7 @@
 		nr++;
 	envp = calloc(nr + 3, sizeof(char *));
 	if (!envp)
-		error(1, errno, "can't allocate env list");
+		fprintf(stderr, "can't allocate env list");
 
 	// ... filtering out any 'LD_PRELOAD' ...
 	nr = 0;
@@ -103,7 +102,7 @@
 	// build the NULL terminated arg list
 	argv = calloc(argc + 1, sizeof(char *));
 	if (!argv)
-		error(1, errno, "can't allocate argument list");
+		fprintf(stderr, "can't allocate argument list");
 
 	memcpy(argv, av, argc * sizeof(char*));
 	return execvpe(argv[0], argv, envp);
@@ -124,33 +123,33 @@
 	len = strlen(name) + 1 + strlen(SYSTEMCTL_SHOW);
 	cmd = malloc(len);
 	if (!cmd)
-		error(1, 0, "can't allocate systemctl command string");
+		fprintf(stderr, "can't allocate systemctl command string");
 
 	sprintf(cmd, SYSTEMCTL_SHOW"%s", name);
 	systemctl = popen(cmd, "r");
 	if (!systemctl)
-		error(1, errno, "can't execute %s", cmd);
+		fprintf(stderr, "can't execute %s", cmd);
 
 	free(cmd);
 	while ((read = getline(&line, &len, systemctl)) != -1) {
 		if (strncmp(line, SYSTEMD_UNIT_VAR, strlen(SYSTEMD_UNIT_VAR)) == 0) {
 			char *ret = strdup(&line[strlen(SYSTEMD_UNIT_VAR)]);
 			if (!ret)
-				error(1, errno, "failed to duplicate string");
+				fprintf(stderr, "failed to duplicate string");
 
 			// trim trailing newline, if any
 			len = strlen(ret);
 			if (len > 0 && ret[len - 1] == '\n')
 				ret[--len] = 0;
 			if (len == 0)
-				error(1, 0, "can't find unit file for service %s", name);
+				fprintf(stderr, "can't find unit file for service %s", name);
 			free(line);
 			pclose(systemctl);
 			return ret;
 		}
 	}
 
-	error(1, 0, "can't find FragmentPath attribute for unit %s", name);
+	fprintf(stderr, "can't find FragmentPath attribute for unit %s", name);
 
 	// never reached: just silence gcc
 	return NULL;
@@ -175,12 +174,12 @@
 	unit = locate_unit(argv[0]);
 	src = fopen(unit, "r");
 	if (!src)
-		error(1, errno, "can't open file %s", unit);
+		fprintf(stderr, "can't open file %s", unit);
 
 	strcpy(dst_path, "/tmp/unit_XXXXXX");
 	dst = mkstemp(dst_path);
 	if (dst < 0)
-		error(1, errno, "can't create tmp file");
+		fprintf(stderr, "can't create tmp file");
 
 	// reset any prior error, to allow later check on errno
 	errno = 0;
@@ -194,27 +193,27 @@
 
 		if (!is_env) {
 			if (write(dst, line, read) < 0)
-				error(1, errno, "can't write '%s' into %s", line, dst_path);
+				fprintf(stderr, "can't write '%s' into %s", line, dst_path);
 		}
 
 		if (append_env &&
 		    (is_env || strncmp(line, SYSTEMD_SERVICE_TAG, strlen(SYSTEMD_SERVICE_TAG)) == 0)) {
 			if (dprintf(dst, "%s%s\n", SYSTEMD_ENV_VAR, MPTCPWRAP_ENV) < 0)
-				error(1, errno, "can't write to env string into %s", dst_path);
+				fprintf(stderr, "can't write to env string into %s", dst_path);
 			append_env = 0;
 		}
 	}
 	if (errno != 0)
-		error(1, errno, "can't read from %s", unit);
+		fprintf(stderr, "can't read from %s", unit);
 	free(line);
 	fclose(src);
 	close(dst);
 
 	if (rename(dst_path, unit) < 0)
-		error(1, errno, "can't rename %s to %s", dst_path, unit);
+		fprintf(stderr, "can't rename %s to %s", dst_path, unit);
 
 	if (system("systemctl daemon-reload") != 0)
-		error(1, errno, "can't reload unit, manual 'systemctl daemon-reload' is required");
+		fprintf(stderr, "can't reload unit, manual 'systemctl daemon-reload' is required");
 
 	printf("mptcp successfully %s on unit %s\n",
 	       enable ? "enabled" : "disabled", unit);
@@ -239,7 +238,7 @@
 	argp_program_version = "mptcpize "VERSION;
 	argp_program_bug_address = "<" PACKAGE_BUGREPORT ">";
 	if (argp_parse(&argp, argc, argv, ARGP_IN_ORDER, &idx, 0) < 0)
-		error(1, errno, "can't parse arguments");
+		fprintf(stderr, "can't parse arguments");
 
 	argc -= idx;
 	argv += idx;
--- a/src/mptcpize.c	2021-07-05 20:06:07.035838944 +0200
+++ b/src/mptcpize.c	2021-07-05 20:06:26.875505617 +0200
@@ -7,8 +7,6 @@
  * Copyright (c) 2021, Red Hat, Inc.
  */
 
-#define  _GNU_SOURCE
-
 #include <linux/limits.h>
 
 #include <sys/types.h>