Only have declassify flag in context when checkmem available

Author: sipa

src/secp256k1.c

@@ -60,14 +60,18 @@ struct secp256k1_context_struct {
     secp256k1_ecmult_gen_context ecmult_gen_ctx;
     secp256k1_callback illegal_callback;
     secp256k1_callback error_callback;
+#if SECP256K1_CHECKMEM_ENABLED
     int declassify;
+#endif
 };
 
 static const secp256k1_context secp256k1_context_static_ = {
     { 0 },
     { secp256k1_default_illegal_callback_fn, 0 },
-    { secp256k1_default_error_callback_fn, 0 },
-    0
+    { secp256k1_default_error_callback_fn, 0 }
+#if SECP256K1_CHECKMEM_ENABLED
+    , 0
+#endif
 };
 const secp256k1_context *secp256k1_context_static = &secp256k1_context_static_;
 const secp256k1_context *secp256k1_context_no_precomp = &secp256k1_context_static_;
@@ -116,7 +120,9 @@ secp256k1_context* secp256k1_context_preallocated_create(void* prealloc, unsigne
     /* Flags have been checked by secp256k1_context_preallocated_size. */
     VERIFY_CHECK((flags & SECP256K1_FLAGS_TYPE_MASK) == SECP256K1_FLAGS_TYPE_CONTEXT);
     secp256k1_ecmult_gen_context_build(&ret->ecmult_gen_ctx);
+#if SECP256K1_CHECKMEM_ENABLED
     ret->declassify = !!(flags & SECP256K1_FLAGS_BIT_CONTEXT_DECLASSIFY);
+#endif
 
     return ret;
 }
@@ -199,7 +205,13 @@ void secp256k1_scratch_space_destroy(const secp256k1_context *ctx, secp256k1_scr
  *  of the software.
  */
 static SECP256K1_INLINE void secp256k1_declassify(const secp256k1_context* ctx, const void *p, size_t len) {
+#if SECP256K1_CHECKMEM_ENABLED
     if (EXPECT(ctx->declassify, 0)) SECP256K1_CHECKMEM_DEFINE(p, len);
+#else
+    (void)ctx;
+    (void)p;
+    (void)len;
+#endif
 }
 
 static int secp256k1_pubkey_load(const secp256k1_context* ctx, secp256k1_ge* ge, const secp256k1_pubkey* pubkey) {