--- ../procps-3.3.17/configure.ac	2021-02-09 11:11:25.000000000 +0100
+++ ./configure.ac	2021-05-08 20:36:49.085413472 +0200
@@ -116,6 +116,22 @@
 
 AC_CHECK_HEADERS(stdio_ext.h, [], [], AC_INCLUDES_DEFAULT)
 
+AC_MSG_CHECKING(for __progname)
+AC_LINK_IFELSE([AC_LANG_SOURCE(
+	[
+		#include <stdio.h>
+		#include <stdlib.h>
+		extern char *__progname;
+		int main(void) {
+			const char *cp = __progname;
+			printf("%s\n", cp);
+			exit(0);
+		}
+	])],
+	AC_DEFINE(HAVE___PROGNAME, 1, [Define if __progname exists])
+	AC_MSG_RESULT(yes),
+	AC_MSG_RESULT(no))
+
 AC_MSG_CHECKING(whether program_invocation_name is defined)
 AC_TRY_COMPILE([#include <errno.h>],
 		[program_invocation_name = "test";],