--- a/unix/configure	2009-04-16 15:25:12.000000000 -0400
+++ b/unix/configure	2023-05-30 15:18:33.670321348 -0400
@@ -408,7 +408,7 @@
 echo Check for errno declaration
 cat > conftest.c << _EOF_
 #include <errno.h>
-main()
+int main()
 {
   errno = 0;
   return 0;
@@ -419,6 +419,8 @@
 
 echo Check for directory libraries
 cat > conftest.c << _EOF_
+#include <sys/types.h>
+#include <dirent.h>
 int main() { return closedir(opendir(".")); }
 _EOF_