Merge bitcoin#880: Add parens around ROUND_TO_ALIGN's parameter.

b6f6498 Add parens around ROUND_TO_ALIGN's parameter. This makes the macro robust against a hypothetical ROUND_TO_ALIGN(foo ? sizeA : size B) invocation. (Russell O'Connor)

Pull request description:

  This makes the macro robust against a hypothetical `ROUND_TO_ALIGN(foo ? sizeA : size B)` invocation.

  See also <https://wiki.sei.cmu.edu/confluence/display/c/PRE01-C.+Use+parentheses+within+macros+around+parameter+names>.

ACKs for top commit:
  sipa:
    ACK b6f6498. This is the way.
  jonasnick:
    utACK b6f6498
  real-or-random:
    utACK b6f6498

Tree-SHA512: 6a2685f959e8ae472259e5ea75fe12e8e6213f56f5aec7603a896c294e6a8833caae25c412607d9c9a3125370a7765a3e506127b101a1b87203f95e326f6c6c6

src/util.h

@@ -113,7 +113,7 @@ static SECP256K1_INLINE void *checked_realloc(const secp256k1_callback* cb, void
 #define ALIGNMENT 16
 #endif
 
-#define ROUND_TO_ALIGN(size) (((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT)
+#define ROUND_TO_ALIGN(size) ((((size) + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT)
 
 /* Assume there is a contiguous memory object with bounds [base, base + max_size)
  * of which the memory range [base, *prealloc_ptr) is already allocated for usage,