Fuzzing build modes (FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) doesn't
necessarily imply that assert() is enabled, according to the manual.
When the current do-nothing is expanded under -Wunused-variable (-Wall),
it results in unused variables in some of the FUZZING_BUILD_MODE...
blocks.
This patch extends the do-nothing to avoid the unused variable.
# include <assert.h>
#else
# ifndef assert /* assert may be already defined, due to prior #include <assert.h> */
-# define assert(condition) ((void)0) /* disable assert (default) */
+# define assert(condition) ((void) (condition)) /* disable assert (default) */
# endif
#endif