src|tests: Address warning -Wstrict-prototypes

Symptom with Clang 15:
> In file included from userinfo.c:20:
> ./userinfo.h:38:27: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
> void invalidate_user_cache(); /* safe to call from signal handler */
>                           ^
>                            void
> [many more]

4 files changed, 14 insertions, 14 deletions

diff --git a/tests/internals/test_common.c b/tests/internals/test_common.c
index 6c10292..449c64a 100644
--- a/tests/internals/test_common.c
+++ b/tests/internals/test_common.c
@@ -3,7 +3,7 @@
 
 int failures = 0;
 
-int run_suite(void (*suite)()) {
+int run_suite(void (*suite)(void)) {
     suite();
     return (failures > 0) ? 1 : 0;
 }
diff --git a/tests/internals/test_common.h b/tests/internals/test_common.h
index 1688add..055fc38 100644
--- a/tests/internals/test_common.h
+++ b/tests/internals/test_common.h
@@ -10,8 +10,8 @@ extern int failures;
 #define TEST_ASSERT(expr) do { if (!(expr)) { printf("Assertion failed: %s:%d: `%s'\n", __FILE__, __LINE__, #expr); ++failures; } } while (0);
 #define NEAR(a, b, eps) (fabs((a) - (b)) < (eps))
 
-int run_suite(void (*suite)());
+int run_suite(void (*suite)(void));
 
-#define TEST_MAIN(suite) int main() { return run_suite(suite); }
+#define TEST_MAIN(suite) int main(void) { return run_suite(suite); }
 
 #endif
diff --git a/tests/internals/test_internals.c b/tests/internals/test_internals.c
index 53f9872..23fa192 100644
--- a/tests/internals/test_internals.c
+++ b/tests/internals/test_internals.c
@@ -6,7 +6,7 @@
 #include <string.h>
 #include <stdlib.h>
 
-static void arena_suite()
+static void arena_suite(void)
 {
     const int iterations = 1000;
     struct arena arena;
@@ -55,7 +55,7 @@ static void test_path_starts_with(const char* path, const char* prefix, bool exp
     }
 }
 
-static void my_dirname_suite()
+static void my_dirname_suite(void)
 {
     char buf[256];
 
@@ -90,7 +90,7 @@ static void my_dirname_suite()
     test_my_dirname(buf, "..");
 }
 
-static void path_starts_with_suite()
+static void path_starts_with_suite(void)
 {
     test_path_starts_with("/a/b/c", "/a/b", true);
     test_path_starts_with("/a/b/c", "/a/b/", true);
@@ -144,7 +144,7 @@ static void path_starts_with_suite()
     test_path_starts_with("/a/b/c", "/", true);
 }
 
-static void sprintf_new_suite() {
+static void sprintf_new_suite(void) {
     char *result;
 
     result = sprintf_new("Hello %d %s", 123, "World");
@@ -214,7 +214,7 @@ static void filter_o_opts_test(const char **init, const char **expected) {
     free(joined_input);
 }
 
-static void filter_o_opts_suite() {
+static void filter_o_opts_suite(void) {
     {
         const char *in[] = {"-obad1", NULL};
         const char *exp[] = {NULL};
@@ -299,7 +299,7 @@ static void filter_o_opts_suite() {
     }
 }
 
-static void test_internal_suite() {
+static void test_internal_suite(void) {
     arena_suite();
     my_dirname_suite();
     path_starts_with_suite();
diff --git a/tests/internals/test_rate_limiter.c b/tests/internals/test_rate_limiter.c
index 09b219e..25e26fb 100644
--- a/tests/internals/test_rate_limiter.c
+++ b/tests/internals/test_rate_limiter.c
@@ -6,12 +6,12 @@ static const double epsilon = 0.000000000001;
 
 static volatile double time_now = 123123.0;
 
-double test_clock()
+double test_clock(void)
 {
     return time_now;
 }
 
-void computes_correct_sleep_times()
+void computes_correct_sleep_times(void)
 {
     time_now = 123123.0;
     RateLimiter limiter;
@@ -29,7 +29,7 @@ void computes_correct_sleep_times()
     rate_limiter_destroy(&limiter);
 }
 
-void works_after_being_idle()
+void works_after_being_idle(void)
 {
     time_now = 123123.0;
     RateLimiter limiter;
@@ -45,7 +45,7 @@ void works_after_being_idle()
     rate_limiter_destroy(&limiter);
 }
 
-void sleeps_correct_amount()
+void sleeps_correct_amount(void)
 {
     RateLimiter limiter;
     rate_limiter_init(&limiter, 10, &gettimeofday_clock);
@@ -58,7 +58,7 @@ void sleeps_correct_amount()
     rate_limiter_destroy(&limiter);
 }
 
-void rate_limiter_suite()
+void rate_limiter_suite(void)
 {
     computes_correct_sleep_times();
     works_after_being_idle();