diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8fe7376ab..6b22b5d60 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -917,7 +917,6 @@ check_include_file_concat("alloca.h"         HAVE_ALLOCA_H)
 check_include_file_concat("arpa/inet.h"      HAVE_ARPA_INET_H)
 check_include_file_concat("arpa/tftp.h"      HAVE_ARPA_TFTP_H)
 check_include_file_concat("assert.h"         HAVE_ASSERT_H)
-check_include_file_concat("err.h"            HAVE_ERR_H)
 check_include_file_concat("errno.h"          HAVE_ERRNO_H)
 check_include_file_concat("fcntl.h"          HAVE_FCNTL_H)
 check_include_file_concat("idn2.h"           HAVE_IDN2_H)
diff --git a/lib/Makefile.netware b/lib/Makefile.netware
index 863bde022..a967b70aa 100644
--- a/lib/Makefile.netware
+++ b/lib/Makefile.netware
@@ -560,7 +560,6 @@ endif
 	@echo $(DL)#define HAVE_ARPA_INET_H 1$(DL) >> $@
 	@echo $(DL)#define HAVE_ASSERT_H 1$(DL) >> $@
 	@echo $(DL)#define HAVE_ERRNO_H 1$(DL) >> $@
-	@echo $(DL)#define HAVE_ERR_H 1$(DL) >> $@
 	@echo $(DL)#define HAVE_FCNTL_H 1$(DL) >> $@
 	@echo $(DL)#define HAVE_GETHOSTBYADDR 1$(DL) >> $@
 	@echo $(DL)#define HAVE_GETHOSTBYNAME 1$(DL) >> $@
diff --git a/lib/config-os400.h b/lib/config-os400.h
index f28aa3e35..07a5a9d5d 100644
--- a/lib/config-os400.h
+++ b/lib/config-os400.h
@@ -97,9 +97,6 @@
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H
 
-/* Define if you have the <err.h> header file. */
-#undef HAVE_ERR_H
-
 /* Define if you have the <fcntl.h> header file. */
 #define HAVE_FCNTL_H
 
diff --git a/lib/config-riscos.h b/lib/config-riscos.h
index 3196f2475..5527c6ad0 100644
--- a/lib/config-riscos.h
+++ b/lib/config-riscos.h
@@ -98,9 +98,6 @@
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H
 
-/* Define if you have the <err.h> header file. */
-#undef HAVE_ERR_H
-
 /* Define if you have the <fcntl.h> header file. */
 #define HAVE_FCNTL_H
 
diff --git a/lib/config-tpf.h b/lib/config-tpf.h
index 997dbadaf..536c1b47f 100644
--- a/lib/config-tpf.h
+++ b/lib/config-tpf.h
@@ -102,10 +102,6 @@
 /* Define to 1 if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H 1
 
-/* Define to 1 if you have the <err.h> header file. */
-/* #undef HAVE_ERR_H */
-#define HAVE_ERR_H 1
-
 /* Define to 1 if you have the <fcntl.h> header file. */
 #define HAVE_FCNTL_H 1
 
diff --git a/lib/config-vxworks.h b/lib/config-vxworks.h
index 0d6cb317f..6cff3cc9a 100644
--- a/lib/config-vxworks.h
+++ b/lib/config-vxworks.h
@@ -119,9 +119,6 @@
 /* Define to 1 if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H 1
 
-/* Define to 1 if you have the <err.h> header file. */
-/* #undef HAVE_ERR_H */
-
 /* Define to 1 if you have the fcntl function. */
 #define HAVE_FCNTL 1
 
diff --git a/lib/config-win32.h b/lib/config-win32.h
index c606ae19d..38105e8d4 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -39,9 +39,6 @@
 /* Define if you have the <errno.h> header file. */
 #define HAVE_ERRNO_H 1
 
-/* Define if you have the <err.h> header file. */
-/* #define HAVE_ERR_H 1 */
-
 /* Define if you have the <fcntl.h> header file. */
 #define HAVE_FCNTL_H 1
 
diff --git a/lib/config-win32ce.h b/lib/config-win32ce.h
index 0bb12fb54..9975dd119 100644
--- a/lib/config-win32ce.h
+++ b/lib/config-win32ce.h
@@ -39,9 +39,6 @@
 /* Define if you have the <errno.h> header file.  */
 /* #define HAVE_ERRNO_H 1 */
 
-/* Define if you have the <err.h> header file.  */
-/* #define HAVE_ERR_H 1 */
-
 /* Define if you have the <fcntl.h> header file.  */
 #define HAVE_FCNTL_H 1
 
diff --git a/lib/curl_config.h.cmake b/lib/curl_config.h.cmake
index 8df8d65c3..20313539e 100644
--- a/lib/curl_config.h.cmake
+++ b/lib/curl_config.h.cmake
@@ -151,9 +151,6 @@
 /* Define to 1 if you have the <errno.h> header file. */
 #cmakedefine HAVE_ERRNO_H 1
 
-/* Define to 1 if you have the <err.h> header file. */
-#cmakedefine HAVE_ERR_H 1
-
 /* Define to 1 if you have the fcntl function. */
 #cmakedefine HAVE_FCNTL 1