[ASan] Support {f}puts(NULL) on Darwin, part 2

Add braces around macro `{ MACRO(); }` to guard against macros that
expand to multiple statements.

llvm-svn: 366488
(cherry picked from commit be7a7ae)

Author: yln

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -1241,8 +1241,9 @@ INTERCEPTOR_WITH_SUFFIX(int, fputs, char *s, void *file) {
   // libc file streams can call user-supplied functions, see fopencookie.
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, fputs, s, file);
-  if (!SANITIZER_MAC || s)
+  if (!SANITIZER_MAC || s) {  // `fputs(NULL, file)` is supported on Darwin.
     COMMON_INTERCEPTOR_READ_RANGE(ctx, s, REAL(strlen)(s) + 1);
+  }
   return REAL(fputs)(s, file);
 }
 #define INIT_FPUTS COMMON_INTERCEPT_FUNCTION(fputs)
@@ -1255,8 +1256,9 @@ INTERCEPTOR(int, puts, char *s) {
   // libc file streams can call user-supplied functions, see fopencookie.
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, puts, s);
-  if (!SANITIZER_MAC || s)
+  if (!SANITIZER_MAC || s) {  // `puts(NULL)` is supported on Darwin.
     COMMON_INTERCEPTOR_READ_RANGE(ctx, s, REAL(strlen)(s) + 1);
+  }
   return REAL(puts)(s);
 }
 #define INIT_PUTS COMMON_INTERCEPT_FUNCTION(puts)