diff --git a/lib/config-vxworks.h b/lib/config-vxworks.h
index a03e341e6..8790f8266 100644
--- a/lib/config-vxworks.h
+++ b/lib/config-vxworks.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -161,9 +161,6 @@
 /* Define to 1 if you have a working fcntl O_NONBLOCK function. */
 #define HAVE_FCNTL_O_NONBLOCK 1
 
-/* Define to 1 if you have the fdopen function. */
-#define HAVE_FDOPEN 1
-
 /* Define to 1 if you have the `fork' function. */
 #define HAVE_FORK 1
 
diff --git a/lib/memdebug.h b/lib/memdebug.h
index 233de65a4..30a8f1c88 100644
--- a/lib/memdebug.h
+++ b/lib/memdebug.h
@@ -8,7 +8,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -80,10 +80,6 @@ CURL_EXTERN RECV_TYPE_RETV curl_dorecv(RECV_TYPE_ARG1 sockfd,
 /* FILE functions */
 CURL_EXTERN FILE *curl_fopen(const char *file, const char *mode, int line,
                              const char *source);
-#ifdef HAVE_FDOPEN
-CURL_EXTERN FILE *curl_fdopen(int filedes, const char *mode, int line,
-                              const char *source);
-#endif
 CURL_EXTERN int curl_fclose(FILE *file, int line, const char *source);
 
 #ifndef MEMDEBUG_NODEFINES
diff --git a/m4/curl-functions.m4 b/m4/curl-functions.m4
index 9f230b3f8..92a017b62 100644
--- a/m4/curl-functions.m4
+++ b/m4/curl-functions.m4
@@ -1168,92 +1168,6 @@ AC_DEFUN([CURL_CHECK_FUNC_FCNTL_O_NONBLOCK], [
   fi
 ])
 
-
-dnl CURL_CHECK_FUNC_FDOPEN
-dnl -------------------------------------------------
-dnl Verify if fdopen is available, prototyped, and
-dnl can be compiled. If all of these are true, and
-dnl usage has not been previously disallowed with
-dnl shell variable curl_disallow_fdopen, then
-dnl HAVE_FDOPEN will be defined.
-
-AC_DEFUN([CURL_CHECK_FUNC_FDOPEN], [
-  AC_REQUIRE([CURL_INCLUDES_STDIO])dnl
-  #
-  tst_links_fdopen="unknown"
-  tst_proto_fdopen="unknown"
-  tst_compi_fdopen="unknown"
-  tst_allow_fdopen="unknown"
-  #
-  AC_MSG_CHECKING([if fdopen can be linked])
-  AC_LINK_IFELSE([
-    AC_LANG_FUNC_LINK_TRY([fdopen])
-  ],[
-    AC_MSG_RESULT([yes])
-    tst_links_fdopen="yes"
-  ],[
-    AC_MSG_RESULT([no])
-    tst_links_fdopen="no"
-  ])
-  #
-  if test "$tst_links_fdopen" = "yes"; then
-    AC_MSG_CHECKING([if fdopen is prototyped])
-    AC_EGREP_CPP([fdopen],[
-      $curl_includes_stdio
-    ],[
-      AC_MSG_RESULT([yes])
-      tst_proto_fdopen="yes"
-    ],[
-      AC_MSG_RESULT([no])
-      tst_proto_fdopen="no"
-    ])
-  fi
-  #
-  if test "$tst_proto_fdopen" = "yes"; then
-    AC_MSG_CHECKING([if fdopen is compilable])
-    AC_COMPILE_IFELSE([
-      AC_LANG_PROGRAM([[
-        $curl_includes_stdio
-      ]],[[
-        if(0 != fdopen(0, 0))
-          return 1;
-      ]])
-    ],[
-      AC_MSG_RESULT([yes])
-      tst_compi_fdopen="yes"
-    ],[
-      AC_MSG_RESULT([no])
-      tst_compi_fdopen="no"
-    ])
-  fi
-  #
-  if test "$tst_compi_fdopen" = "yes"; then
-    AC_MSG_CHECKING([if fdopen usage allowed])
-    if test "x$curl_disallow_fdopen" != "xyes"; then
-      AC_MSG_RESULT([yes])
-      tst_allow_fdopen="yes"
-    else
-      AC_MSG_RESULT([no])
-      tst_allow_fdopen="no"
-    fi
-  fi
-  #
-  AC_MSG_CHECKING([if fdopen might be used])
-  if test "$tst_links_fdopen" = "yes" &&
-     test "$tst_proto_fdopen" = "yes" &&
-     test "$tst_compi_fdopen" = "yes" &&
-     test "$tst_allow_fdopen" = "yes"; then
-    AC_MSG_RESULT([yes])
-    AC_DEFINE_UNQUOTED(HAVE_FDOPEN, 1,
-      [Define to 1 if you have the fdopen function.])
-    curl_cv_func_fdopen="yes"
-  else
-    AC_MSG_RESULT([no])
-    curl_cv_func_fdopen="no"
-  fi
-])
-
-
 dnl CURL_CHECK_FUNC_FGETXATTR
 dnl -------------------------------------------------
 dnl Verify if fgetxattr is available, prototyped, and