Remove some gcc/clang specific attributes we don't support

Reviewed-by: NBernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/5105)

crypto/ec/curve448/curve448_tables.c

@@ -14,7 +14,7 @@
 #include "point_448.h"
 
 const gf curve448_precomputed_base_as_fe[240]
-VECTOR_ALIGNED __attribute__((visibility("hidden"))) = {
+VECTOR_ALIGNED = {
   {FIELD_LITERAL(0x00cc3b062366f4cc,0x003d6e34e314aa3c,0x00d51c0a7521774d,0x0094e060eec6ab8b,0x00d21291b4d80082,0x00befed12b55ef1e,0x00c3dd2df5c94518,0x00e0a7b112b8d4e6)},
   {FIELD_LITERAL(0x0019eb5608d8723a,0x00d1bab52fb3aedb,0x00270a7311ebc90c,0x0037c12b91be7f13,0x005be16cd8b5c704,0x003e181acda888e1,0x00bc1f00fc3fc6d0,0x00d3839bfa319e20)},
   {FIELD_LITERAL(0x003caeb88611909f,0x00ea8b378c4df3d4,0x00b3295b95a5a19a,0x00a65f97514bdfb5,0x00b39efba743cab1,0x0016ba98b862fd2d,0x0001508812ee71d7,0x000a75740eea114a)},
@@ -257,7 +257,7 @@ VECTOR_ALIGNED __attribute__((visibility("hidden"))) = {
   {FIELD_LITERAL(0x00445f1263983be0,0x004cf371dda45e6a,0x00744a89d5a310e7,0x001f20ce4f904833,0x00e746edebe66e29,0x000912ab1f6c153d,0x00f61d77d9b2444c,0x0001499cd6647610)}
 };
 const gf curve448_precomputed_wnaf_as_fe[96]
-VECTOR_ALIGNED __attribute__((visibility("hidden"))) = {
+VECTOR_ALIGNED = {
   {FIELD_LITERAL(0x00303cda6feea532,0x00860f1d5a3850e4,0x00226b9fa4728ccd,0x00e822938a0a0c0c,0x00263a61c9ea9216,0x001204029321b828,0x006a468360983c65,0x0002846f0a782143)},
   {FIELD_LITERAL(0x00303cda6feea532,0x00860f1d5a3850e4,0x00226b9fa4728ccd,0x006822938a0a0c0c,0x00263a61c9ea9215,0x001204029321b828,0x006a468360983c65,0x0082846f0a782143)},
   {FIELD_LITERAL(0x00ef8e22b275198d,0x00b0eb141a0b0e8b,0x001f6789da3cb38c,0x006d2ff8ed39073e,0x00610bdb69a167f3,0x00571f306c9689b4,0x00f557e6f84b2df8,0x002affd38b2c86db)},

crypto/ec/curve448/ed448.h

@@ -69,8 +69,7 @@ c448_error_t c448_ed448_sign(
                         const uint8_t pubkey[EDDSA_448_PUBLIC_BYTES],
                         const uint8_t *message, size_t message_len,
                         uint8_t prehashed, const uint8_t *context,
-                        size_t context_len)
-                        __attribute__ ((nonnull(1, 2, 3)));
+                        size_t context_len);
 
 /*
  * EdDSA signing with prehash.
@@ -95,8 +94,7 @@ c448_error_t c448_ed448_sign_prehash(
                         const uint8_t pubkey[EDDSA_448_PUBLIC_BYTES],
                         const uint8_t hash[64],
                         const uint8_t *context,
-                        size_t context_len)
-                        __attribute__ ((nonnull(1, 2, 3, 4)));
+                        size_t context_len);
 
 /*
  * EdDSA signature verification.
@@ -123,8 +121,7 @@ c448_error_t c448_ed448_verify(const uint8_t
                                  pubkey[EDDSA_448_PUBLIC_BYTES],
                                  const uint8_t *message, size_t message_len,
                                  uint8_t prehashed, const uint8_t *context,
-                                 uint8_t context_len)
-                                 __attribute__ ((nonnull(1, 2)));
+                                 uint8_t context_len);
 
 /*
  * EdDSA signature verification.
@@ -149,8 +146,7 @@ c448_error_t c448_ed448_verify_prehash(
                     const uint8_t pubkey[EDDSA_448_PUBLIC_BYTES],
                     const uint8_t hash[64],
                     const uint8_t *context,
-                    uint8_t context_len)
-                    __attribute__ ((nonnull(1, 2)));
+                    uint8_t context_len);
 
 /*
  * EdDSA point encoding.  Used internally, exposed externally.