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, 7 insertions, 7 deletions

diff --git a/auto/types b/auto/types
index 91d53b6f..c0a871dd 100644
--- a/auto/types
+++ b/auto/types
@@ -18,7 +18,7 @@ nxt_feature_incs=
 nxt_feature_libs=
 nxt_feature_test="#include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(int));
                       return 0;
                   }"
@@ -32,7 +32,7 @@ nxt_feature_incs=
 nxt_feature_libs=
 nxt_feature_test="#include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(long));
                       return 0;
                   }"
@@ -46,7 +46,7 @@ nxt_feature_incs=
 nxt_feature_libs=
 nxt_feature_test="#include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(long long));
                       return 0;
                   }"
@@ -60,7 +60,7 @@ nxt_feature_incs=
 nxt_feature_libs=
 nxt_feature_test="#include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(void *));
                       return 0;
                   }"
@@ -80,7 +80,7 @@ nxt_feature_incs=
 nxt_feature_libs=
 nxt_feature_test="#include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(size_t));
                       return 0;
                   }"
@@ -96,7 +96,7 @@ nxt_feature_test="#define _FILE_OFFSET_BITS  64
                   #include <unistd.h>
                   #include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(off_t));
                       return 0;
                   }"
@@ -111,7 +111,7 @@ nxt_feature_libs=
 nxt_feature_test="#include <time.h>
                   #include <stdio.h>
 
-                  int main() {
+                  int main(void) {
                       printf(\"%d\", (int) sizeof(time_t));
                       return 0;
                   }"