diff --git a/library/alignment.h b/library/alignment.h
index 14a86cf377..db835955b6 100644
--- a/library/alignment.h
+++ b/library/alignment.h
@@ -76,10 +76,10 @@ typedef uint64_t __packed mbedtls_uint64_unaligned_t;
  * Tested with several versions of GCC from 4.5.0 up to 13.2.0
  * We don't enable for older than 4.5.0 as this has not been tested.
  */
- #define UINT_UNALIGNED_UNION
-typedef union { uint16_t x; } __attribute__((packed)) mbedtls_uint16_unaligned_t;
-typedef union { uint32_t x; } __attribute__((packed)) mbedtls_uint32_unaligned_t;
-typedef union { uint64_t x; } __attribute__((packed)) mbedtls_uint64_unaligned_t;
+ #define UINT_UNALIGNED_STRUCT
+typedef struct { uint16_t x; } __attribute__((packed)) mbedtls_uint16_unaligned_t;
+typedef struct { uint32_t x; } __attribute__((packed)) mbedtls_uint32_unaligned_t;
+typedef struct { uint64_t x; } __attribute__((packed)) mbedtls_uint64_unaligned_t;
  #endif
 
 /*
@@ -106,7 +106,7 @@ static inline uint16_t mbedtls_get_unaligned_uint16(const void *p)
 #if defined(UINT_UNALIGNED)
     mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
     r = *p16;
-#elif defined(UINT_UNALIGNED_UNION)
+#elif defined(UINT_UNALIGNED_STRUCT)
     mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
     r = p16->x;
 #else
@@ -132,7 +132,7 @@ static inline void mbedtls_put_unaligned_uint16(void *p, uint16_t x)
 #if defined(UINT_UNALIGNED)
     mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
     *p16 = x;
-#elif defined(UINT_UNALIGNED_UNION)
+#elif defined(UINT_UNALIGNED_STRUCT)
     mbedtls_uint16_unaligned_t *p16 = (mbedtls_uint16_unaligned_t *) p;
     p16->x = x;
 #else
@@ -158,7 +158,7 @@ static inline uint32_t mbedtls_get_unaligned_uint32(const void *p)
 #if defined(UINT_UNALIGNED)
     mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
     r = *p32;
-#elif defined(UINT_UNALIGNED_UNION)
+#elif defined(UINT_UNALIGNED_STRUCT)
     mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
     r = p32->x;
 #else
@@ -184,7 +184,7 @@ static inline void mbedtls_put_unaligned_uint32(void *p, uint32_t x)
 #if defined(UINT_UNALIGNED)
     mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
     *p32 = x;
-#elif defined(UINT_UNALIGNED_UNION)
+#elif defined(UINT_UNALIGNED_STRUCT)
     mbedtls_uint32_unaligned_t *p32 = (mbedtls_uint32_unaligned_t *) p;
     p32->x = x;
 #else
@@ -210,7 +210,7 @@ static inline uint64_t mbedtls_get_unaligned_uint64(const void *p)
 #if defined(UINT_UNALIGNED)
     mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
     r = *p64;
-#elif defined(UINT_UNALIGNED_UNION)
+#elif defined(UINT_UNALIGNED_STRUCT)
     mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
     r = p64->x;
 #else
@@ -236,7 +236,7 @@ static inline void mbedtls_put_unaligned_uint64(void *p, uint64_t x)
 #if defined(UINT_UNALIGNED)
     mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
     *p64 = x;
-#elif defined(UINT_UNALIGNED_UNION)
+#elif defined(UINT_UNALIGNED_STRUCT)
     mbedtls_uint64_unaligned_t *p64 = (mbedtls_uint64_unaligned_t *) p;
     p64->x = x;
 #else