Fixed main() prototypes in auto tests.

Future releases of GCC are planning to remove[0] default support for
some old features that were removed from C99 but GCC still accepts.

We can test for these changes by using the following -Werror=
directives

  -Werror=implicit-int
  -Werror=implicit-function-declaration
  -Werror=int-conversion
  -Werror=strict-prototypes
  -Werror=old-style-definition

Doing so revealed an issue with the auto/ tests in that the test
programs always define main as

  int main()

rather than

  int main(void)

which results in a bunch of errors like

build/autotest.c:3:23: error: function declaration isn't a prototype [-Werror=strict-prototypes]
    3 |                   int main() {
      |                       ^~~~
build/autotest.c: In function 'main':
build/autotest.c:3:23: error: old-style function definition [-Werror=old-style-definition]

The fix was easy, it only required fixing the main prototype with

  find -type f -exec sed -i 's/int main() {/int main(void) {/g' {} \;

Regardless of these upcoming GCC changes, this is probably a good thing
to do anyway for correctness.

[0]: https://fedoraproject.org/wiki/Changes/PortingToModernC

Link: <https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/CJXKTLXJUPZ4F2C2VQOTNMEA5JAUPMBD/>
Link: <https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/6SGHPHPAXKCVJ6PUZ57WVDQ5TDBVIRMF/>
Reviewed-by: Alejandro Colomar <alx@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/auto/shmem b/auto/shmem
index bfe0ee4a..c434a58f 100644
--- a/auto/shmem
+++ b/auto/shmem
@@ -18,7 +18,7 @@ nxt_feature_test="#include <sys/mman.h>
                   #include <sys/stat.h>
                   #include <sys/types.h>
 
-                  int main() {
+                  int main(void) {
                       int         ret;
                       static char name[] = \"/unit.configure\";
 
@@ -62,7 +62,7 @@ if [ $nxt_found = no ]; then
                       #include <sys/stat.h>
                       #include <sys/types.h>
 
-                      int main() {
+                      int main(void) {
                           static char name[] = \"/tmp/unit.configure\";
 
                           shm_unlink(name);
@@ -94,7 +94,7 @@ nxt_feature_test="#include <sys/mman.h>
                   #include <fcntl.h>
                   #include <sys/stat.h>
 
-                  int main() {
+                  int main(void) {
                       int fd = shm_open(SHM_ANON, O_RDWR, S_IRUSR | S_IWUSR);
                       if (fd == -1)
                           return 1;
@@ -119,7 +119,7 @@ nxt_feature_test="#include <linux/memfd.h>
                   #include <unistd.h>
                   #include <sys/syscall.h>
 
-                  int main() {
+                  int main(void) {
                       static char name[] = \"/unit.configure\";
 
                       int fd = syscall(SYS_memfd_create, name, MFD_CLOEXEC);