Update brace style.

Add braces around single-line blocks, and remove line breaks before
function-opening braces.

This resolves #537.

test/include/test/btalloc.h

@@ -8,13 +8,12 @@ btalloc_n_proto(1)
 
 #define	btalloc_n_gen(n)						\
 void *									\
-btalloc_##n(size_t size, unsigned bits)					\
-{									\
+btalloc_##n(size_t size, unsigned bits) {				\
 	void *p;							\
 									\
-	if (bits == 0)							\
+	if (bits == 0) {						\
 		p = mallocx(size, 0);					\
-	else {								\
+	} else {							\
 		switch (bits & 0x1U) {					\
 		case 0:							\
 			p = (btalloc_0(size, bits >> 1));		\