diff --git a/config.h.in b/config.h.in
index 678ebd0c6..90be6906b 100644
--- a/config.h.in
+++ b/config.h.in
@@ -967,6 +967,9 @@
 /* Define to 1 if you have the `vasprintf' function. */
 #undef HAVE_VASPRINTF
 
+/* Define to 1 if you have the `va_copy' function. */
+#undef HAVE_VA_COPY
+
 /* Define to 1 if you have the `vsnprintf' function. */
 #undef HAVE_VSNPRINTF
 
@@ -1018,6 +1021,9 @@
 /* Define to 1 if your crt0.o defines the __progname symbol for you. */
 #undef HAVE___PROGNAME
 
+/* Define to 1 if you have the `__va_copy' function. */
+#undef HAVE___VA_COPY
+
 /* Define to 1 if you want the hostname to be entered into the log file. */
 #undef HOST_IN_LOG
 
diff --git a/configure b/configure
index 168cbfa72..d5275c6f3 100755
--- a/configure
+++ b/configure
@@ -23316,6 +23316,78 @@ fi
 esac
 LIBS="$OLIBS"
 
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for va_copy" >&5
+printf %s "checking for va_copy... " >&6; }
+if test ${sudo_cv_func_va_copy+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdarg.h>
+	va_list ap1, ap2;
+int
+main (void)
+{
+va_copy(ap1, ap2);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  sudo_cv_func_va_copy=yes
+else $as_nop
+  sudo_cv_func_va_copy=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $sudo_cv_func_va_copy" >&5
+printf "%s\n" "$sudo_cv_func_va_copy" >&6; }
+if test "$sudo_cv_func_va_copy" = "yes"; then
+    printf "%s\n" "#define HAVE_VA_COPY 1" >>confdefs.h
+
+else
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for __va_copy" >&5
+printf %s "checking for __va_copy... " >&6; }
+if test ${sudo_cv_func___va_copy+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdarg.h>
+	    va_list ap1, ap2;
+int
+main (void)
+{
+__va_copy(ap1, ap2);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  sudo_cv_func___va_copy=yes
+else $as_nop
+  sudo_cv_func___va_copy=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $sudo_cv_func___va_copy" >&5
+printf "%s\n" "$sudo_cv_func___va_copy" >&6; }
+    if test "$sudo_cv_func___va_copy" = "yes"; then
+	printf "%s\n" "#define HAVE___VA_COPY 1" >>confdefs.h
+
+    fi
+fi
+
 
   for ac_func in getprogname
 do :
@@ -31782,6 +31854,8 @@ fi
 
 
 
+
+
 
 
 
diff --git a/configure.ac b/configure.ac
index ea405644a..d1cf9ebbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3226,6 +3226,27 @@ case " $LIBOBJS " in
 esac
 LIBS="$OLIBS"
 
+dnl
+dnl Check for va_copy or __va_copy in stdarg.h
+dnl
+AC_CACHE_CHECK([for va_copy], sudo_cv_func_va_copy, [
+    AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdarg.h>
+	va_list ap1, ap2;]], [[va_copy(ap1, ap2);]])],
+	[sudo_cv_func_va_copy=yes], [sudo_cv_func_va_copy=no])
+])
+if test "$sudo_cv_func_va_copy" = "yes"; then
+    AC_DEFINE(HAVE_VA_COPY)
+else
+    AC_CACHE_CHECK([for __va_copy], sudo_cv_func___va_copy, [
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdarg.h>
+	    va_list ap1, ap2;]], [[__va_copy(ap1, ap2);]])],
+	    [sudo_cv_func___va_copy=yes], [sudo_cv_func___va_copy=no])
+    ])
+    if test "$sudo_cv_func___va_copy" = "yes"; then
+	AC_DEFINE(HAVE___VA_COPY)
+    fi
+fi
+
 dnl
 dnl Check for getprogname()/setprogname() or __progname
 dnl
@@ -5128,6 +5149,8 @@ AH_TEMPLATE(HAVE_SSL_CTX_SET_MIN_PROTO_VERSION, [Define to 1 if you have the `SS
 AH_TEMPLATE(HAVE_SSL_CTX_SET_CIPHERSUITES, [Define to 1 if you have the `SSL_CTX_set_ciphersuites' function or macro.])
 AH_TEMPLATE(SUDOERS_LOG_CLIENT, [Define to 1 to compile support for sudo_logsrvd in the sudoers plugin.])
 AH_TEMPLATE(HAVE_FALLTHROUGH_ATTRIBUTE, [Define to 1 if the compiler supports the fallthrough attribute.])
+AH_TEMPLATE(HAVE_VA_COPY, [Define to 1 if you have the `va_copy' function.])
+AH_TEMPLATE(HAVE___VA_COPY, [Define to 1 if you have the `__va_copy' function.])
 
 dnl
 dnl Bits to copy verbatim into config.h.in
diff --git a/include/sudo_compat.h b/include/sudo_compat.h
index 6bc74a99d..971443dd9 100644
--- a/include/sudo_compat.h
+++ b/include/sudo_compat.h
@@ -91,8 +91,8 @@
 /*
  * Pre-C99 compilers may lack a va_copy macro.
  */
-#ifndef va_copy
-# ifdef __va_copy
+#ifndef HAVE_VA_COPY
+# ifdef HAVE___VA_COPY
 #  define va_copy(d, s) __va_copy(d, s)
 # else
 #  define va_copy(d, s) memcpy(&(d), &(s), sizeof(d));