#include unistd.h for write prototype on Unix build.

src/sbbs3/scfg/makehelp.c

@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #if defined(__unix__)
+	#include <unistd.h>		/* write */
 	#define O_BINARY 0
 #else
 	#include <io.h>	/* open */