e_os.h does not belong with the exported headers.  Do not put it there
and make all files the depend on it include it without prefixing it
with openssl/.

This means that all Makefiles will have $(TOP) as one of the include
directories.
diff --git a/crypto/rsa/rsa_test.c b/crypto/rsa/rsa_test.c
index d91e045..e882b5b 100644
--- a/crypto/rsa/rsa_test.c
+++ b/crypto/rsa/rsa_test.c
@@ -3,7 +3,7 @@
 #include <stdio.h>
 #include <string.h>
 
-#include "openssl/e_os.h"
+#include "e_os.h"
 
 #include <openssl/crypto.h>
 #include <openssl/err.h>