Allow to forward declare of public structs #1215
Thanks to forward declare we can declare `struct` in our header file instead making #include
diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 87535ab..d2098eb 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -53,7 +53,8 @@
/**
* \brief The GCM context structure.
*/
-typedef struct {
+typedef struct mbedtls_gcm_context
+{
mbedtls_cipher_context_t cipher_ctx; /*!< The cipher context used. */
uint64_t HL[16]; /*!< Precalculated HTable low. */
uint64_t HH[16]; /*!< Precalculated HTable high. */