When I make the configure of ctags-5.8 has the undeclared identifie Erro

On Mac 10.15 When i make the configure of ctags-5.8, I have the problem:

gcc -I. -I. -DHAVE_CONFIG_H -g -O2 -c main.c

In file included from main.c:62:
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/dirent.h:80:2: error:
  use of undeclared identifier 'unused'
    __unused long   __padding; /* (__dd_rewind space left for bincompat) */
    ^
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/cdefs.h:161:40: note:
  expanded from macro '__unused'
#define __unused        __attribute__((__unused__))
                                   ^
./general.h:60:37: note: expanded from macro '__unused__'
# define __unused__  __attribute__((unused))
                                ^
1 error generated.
make: *** [main.o] Error 1

gcc -v :

Configured with: ../configure --build=x86_64-apple-darwin19 --
Thread model: posix
gcc version 8.3.0 (Homebrew GCC 8.3.0_2)