These changes appear to be for autoconf-generated code only, so there is
nothing to upstream to aprsd.  (The issues should go away with any new
release.)

diff --git a/configure b/configure
index 573145de07e658e9..df75bd55673f1943 100755
--- a/configure
+++ b/configure
@@ -2132,7 +2132,6 @@ else
   fi
 fi
 for ac_declaration in \
-   ''\
    '#include <stdlib.h>' \
    'extern "C" void std::exit (int) throw (); using std::exit;' \
    'extern "C" void std::exit (int); using std::exit;' \
@@ -2958,7 +2957,6 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
   for ac_declaration in \
-   ''\
    '#include <stdlib.h>' \
    'extern "C" void std::exit (int) throw (); using std::exit;' \
    'extern "C" void std::exit (int); using std::exit;' \
@@ -3671,8 +3669,8 @@ main ()
   for (i = 0; i < 256; i++)
     if (XOR (islower (i), ISLOWER (i))
         || toupper (i) != TOUPPER (i))
-      exit(2);
-  exit (0);
+      return 2;
+  return 0;
 }
 _ACEOF
 rm -f conftest$ac_exeext
@@ -4102,8 +4100,8 @@ main ()
   for (i = 0; i < 256; i++)
     if (XOR (islower (i), ISLOWER (i))
         || toupper (i) != TOUPPER (i))
-      exit(2);
-  exit (0);
+      return 2;
+  return 0;
 }
 _ACEOF
 rm -f conftest$ac_exeext
@@ -5413,15 +5411,13 @@ else
   cat >conftest.$ac_ext <<_ACEOF
 /* By Ruediger Kuhlmann. */
       #include <sys/types.h>
-      #if HAVE_UNISTD_H
-      # include <unistd.h>
-      #endif
+      #include <unistd.h>
       /* Some systems only have a dummy stub for fork() */
       int main ()
       {
         if (fork() < 0)
-          exit (1);
-        exit (0);
+          return 1;
+        return 0;
       }
 _ACEOF
 rm -f conftest$ac_exeext
@@ -5917,6 +5913,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
+#include <string.h>
 
 int
 main ()
@@ -5925,7 +5922,7 @@ main ()
   /* Some versions of memcmp are not 8-bit clean.  */
   char c0 = 0x40, c1 = 0x80, c2 = 0x81;
   if (memcmp(&c0, &c2, 1) >= 0 || memcmp(&c1, &c2, 1) >= 0)
-    exit (1);
+    return 1;
 
   /* The Next x86 OpenStep bug shows up only when comparing 16 bytes
      or more and with at least one buffer not starting on a 4-byte boundary.
@@ -5941,9 +5938,9 @@ main ()
         strcpy (a, "--------01111111");
         strcpy (b, "--------10000000");
         if (memcmp (a, b, 16) >= 0)
-          exit (1);
+          return 1;
       }
-    exit (0);
+    return 0;
   }
 
   ;