Add sys/select.h to sys/types.h

This was triggered by gcc for some reason It included sys/types.h and
assumed sys/select.h to be there. And that seams to be the case in musl.

The problem with relibc here is that sys/types.h is are part of relibc
"include/*.h" files, while sys/select.h is generated by cbindgen. That
makes it impossible to #include select.h in types.h epsecially that
there are files like fcntl.c that uses types.h. They would complain
about missing headers. I fixed this by renaming sys/types.h to
sys/types_internal.h and then generating types.h using cbindgen as well
except for that. however fcntl and dlmalloc can include types_internal
instead of types.h

include/sys/types_internal.h

@@ -1,5 +1,5 @@
-#ifndef _SYS_TYPES_H
-#define _SYS_TYPES_H
+#ifndef _SYS_TYPES_INTERNAL_H
+#define _SYS_TYPES_INTERNAL_H
 #include <stddef.h>
 
 typedef long blksize_t;
@@ -31,5 +31,4 @@ typedef unsigned long u_long, ulong;
 typedef long long quad_t;
 typedef unsigned long long u_quad_t;
 typedef char *caddr_t;
-
-#endif /* _SYS_TYPES_H */
+#endif /* _SYS_TYPES_INTERNAL_H */