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/apps/apps.h b/apps/apps.h
index db3fe03..fb2e01b 100644
--- a/apps/apps.h
+++ b/apps/apps.h
@@ -59,7 +59,7 @@
 #ifndef HEADER_APPS_H
 #define HEADER_APPS_H
 
-#include "openssl/e_os.h"
+#include "e_os.h"
 
 #include <openssl/buffer.h>
 #include <openssl/bio.h>