diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 6fbd018..afe7a81 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -43,13 +43,31 @@
 #include "md.h"
 #endif
 
-#if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C)
-#include "x509.h"
-#endif
-
 #define MBEDTLS_ERR_OID_NOT_FOUND                         -0x002E  /**< OID is not found. */
 #define MBEDTLS_ERR_OID_BUF_TOO_SMALL                     -0x000B  /**< output buffer is too small */
 
+/* This is for the benefit of X.509, but defined here in order to avoid
+ * having a "backwards" include of x.509.h here */
+/*
+ * X.509 extension types (internal, arbitrary values for bitsets)
+ */
+#define MBEDTLS_OID_X509_EXT_AUTHORITY_KEY_IDENTIFIER    (1 << 0)
+#define MBEDTLS_OID_X509_EXT_SUBJECT_KEY_IDENTIFIER      (1 << 1)
+#define MBEDTLS_OID_X509_EXT_KEY_USAGE                   (1 << 2)
+#define MBEDTLS_OID_X509_EXT_CERTIFICATE_POLICIES        (1 << 3)
+#define MBEDTLS_OID_X509_EXT_POLICY_MAPPINGS             (1 << 4)
+#define MBEDTLS_OID_X509_EXT_SUBJECT_ALT_NAME            (1 << 5)
+#define MBEDTLS_OID_X509_EXT_ISSUER_ALT_NAME             (1 << 6)
+#define MBEDTLS_OID_X509_EXT_SUBJECT_DIRECTORY_ATTRS     (1 << 7)
+#define MBEDTLS_OID_X509_EXT_BASIC_CONSTRAINTS           (1 << 8)
+#define MBEDTLS_OID_X509_EXT_NAME_CONSTRAINTS            (1 << 9)
+#define MBEDTLS_OID_X509_EXT_POLICY_CONSTRAINTS          (1 << 10)
+#define MBEDTLS_OID_X509_EXT_EXTENDED_KEY_USAGE          (1 << 11)
+#define MBEDTLS_OID_X509_EXT_CRL_DISTRIBUTION_POINTS     (1 << 12)
+#define MBEDTLS_OID_X509_EXT_INIHIBIT_ANYPOLICY          (1 << 13)
+#define MBEDTLS_OID_X509_EXT_FRESHEST_CRL                (1 << 14)
+#define MBEDTLS_OID_X509_EXT_NS_CERT_TYPE                (1 << 16)
+
 /*
  * Top level OID tuples
  */
diff --git a/include/mbedtls/x509.h b/include/mbedtls/x509.h
index d6db9c6..d9361b3 100644
--- a/include/mbedtls/x509.h
+++ b/include/mbedtls/x509.h
@@ -142,24 +142,26 @@
  *
  * Comments refer to the status for using certificates. Status can be
  * different for writing certificates or reading CRLs or CSRs.
+ *
+ * Those are defined in oid.h as oid.c needs them in a data structure. Since
+ * these were previously defined here, let's have aliases for compatibility.
  */
-#define MBEDTLS_X509_EXT_AUTHORITY_KEY_IDENTIFIER    (1 << 0)
-#define MBEDTLS_X509_EXT_SUBJECT_KEY_IDENTIFIER      (1 << 1)
-#define MBEDTLS_X509_EXT_KEY_USAGE                   (1 << 2)
-#define MBEDTLS_X509_EXT_CERTIFICATE_POLICIES        (1 << 3)
-#define MBEDTLS_X509_EXT_POLICY_MAPPINGS             (1 << 4)
-#define MBEDTLS_X509_EXT_SUBJECT_ALT_NAME            (1 << 5)    /* Supported (DNS) */
-#define MBEDTLS_X509_EXT_ISSUER_ALT_NAME             (1 << 6)
-#define MBEDTLS_X509_EXT_SUBJECT_DIRECTORY_ATTRS     (1 << 7)
-#define MBEDTLS_X509_EXT_BASIC_CONSTRAINTS           (1 << 8)    /* Supported */
-#define MBEDTLS_X509_EXT_NAME_CONSTRAINTS            (1 << 9)
-#define MBEDTLS_X509_EXT_POLICY_CONSTRAINTS          (1 << 10)
-#define MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE          (1 << 11)
-#define MBEDTLS_X509_EXT_CRL_DISTRIBUTION_POINTS     (1 << 12)
-#define MBEDTLS_X509_EXT_INIHIBIT_ANYPOLICY          (1 << 13)
-#define MBEDTLS_X509_EXT_FRESHEST_CRL                (1 << 14)
-
-#define MBEDTLS_X509_EXT_NS_CERT_TYPE                (1 << 16)
+#define MBEDTLS_X509_EXT_AUTHORITY_KEY_IDENTIFIER MBEDTLS_OID_X509_EXT_AUTHORITY_KEY_IDENTIFIER
+#define MBEDTLS_X509_EXT_SUBJECT_KEY_IDENTIFIER   MBEDTLS_OID_X509_EXT_SUBJECT_KEY_IDENTIFIER
+#define MBEDTLS_X509_EXT_KEY_USAGE                MBEDTLS_OID_X509_EXT_KEY_USAGE
+#define MBEDTLS_X509_EXT_CERTIFICATE_POLICIES     MBEDTLS_OID_X509_EXT_CERTIFICATE_POLICIES
+#define MBEDTLS_X509_EXT_POLICY_MAPPINGS          MBEDTLS_OID_X509_EXT_POLICY_MAPPINGS
+#define MBEDTLS_X509_EXT_SUBJECT_ALT_NAME         MBEDTLS_OID_X509_EXT_SUBJECT_ALT_NAME         /* Supported (DNS) */
+#define MBEDTLS_X509_EXT_ISSUER_ALT_NAME          MBEDTLS_OID_X509_EXT_ISSUER_ALT_NAME
+#define MBEDTLS_X509_EXT_SUBJECT_DIRECTORY_ATTRS  MBEDTLS_OID_X509_EXT_SUBJECT_DIRECTORY_ATTRS
+#define MBEDTLS_X509_EXT_BASIC_CONSTRAINTS        MBEDTLS_OID_X509_EXT_BASIC_CONSTRAINTS        /* Supported */
+#define MBEDTLS_X509_EXT_NAME_CONSTRAINTS         MBEDTLS_OID_X509_EXT_NAME_CONSTRAINTS
+#define MBEDTLS_X509_EXT_POLICY_CONSTRAINTS       MBEDTLS_OID_X509_EXT_POLICY_CONSTRAINTS
+#define MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE       MBEDTLS_OID_X509_EXT_EXTENDED_KEY_USAGE
+#define MBEDTLS_X509_EXT_CRL_DISTRIBUTION_POINTS  MBEDTLS_OID_X509_EXT_CRL_DISTRIBUTION_POINTS
+#define MBEDTLS_X509_EXT_INIHIBIT_ANYPOLICY       MBEDTLS_OID_X509_EXT_INIHIBIT_ANYPOLICY
+#define MBEDTLS_X509_EXT_FRESHEST_CRL             MBEDTLS_OID_X509_EXT_FRESHEST_CRL
+#define MBEDTLS_X509_EXT_NS_CERT_TYPE             MBEDTLS_OID_X509_EXT_NS_CERT_TYPE
 
 /*
  * Storage format identifiers