Tests: Add function prototype for main

Ordinarily, `main` is exempt from -Wmissing-prototypes. However,
if it's re-#define'd, it isn't. To allow -Wmissing-prototypes
in baremetal platforms wrapping `main`, this commit adds an
explicit prototype for `main` in all test applications.

Signed-off-by: Hanno Becker <beckphan@amazon.co.uk>

Author: hanno-becker

test/acvp/acvp_mlkem.c

@@ -192,6 +192,10 @@ static MLK_NOINLINE void acvp_mlkem_keyGen_AFT(
   print_hex("dk", dk, sizeof(dk));
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(int argc, char *argv[]);
+#endif
 int main(int argc, char *argv[])
 {
   acvp_mode mode;

test/bench/bench_components_mlkem.c

@@ -362,6 +362,10 @@ static int bench(void)
   return 0;
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   enable_cyclecounter();

test/bench/bench_mlkem.c

@@ -157,6 +157,10 @@ static int bench(void)
   return 0;
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   enable_cyclecounter();

test/src/gen_KAT.c

@@ -42,6 +42,10 @@ static void print_hex(const char *label, const uint8_t *data, size_t size)
   printf("\n");
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   unsigned i;

test/src/test_alloc.c

@@ -436,6 +436,10 @@ static int test_check_sk_alloc_failure(test_ctx_t *ctx)
     }                                                                        \
   } while (0)
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   MLK_ALIGN uint8_t bump_buffer[MLK_BUMP_ALLOC_SIZE];

test/src/test_mlkem.c

@@ -160,6 +160,10 @@ static int test_invalid_ciphertext(void)
   return 0;
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   unsigned i;

test/src/test_rng_fail.c

@@ -199,6 +199,10 @@ static int test_check_sk_rng_failure(void)
   return 0;
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   if (test_keygen_rng_failure() != 0)

test/src/test_stack.c

@@ -43,6 +43,10 @@ static void test_decaps_only(void)
   (void)ret; /* Ignore return value - we only care about stack measurement */
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(int argc, char *argv[]);
+#endif
 int main(int argc, char *argv[])
 {
   if (argc != 2)

test/src/test_unit.c

@@ -30,6 +30,13 @@
 #endif
 #endif /* !NUM_RANDOM_TESTS_REJ_UNIFORM */
 
+/* Largest absolute constant-coefficient value the invNTT overflow test sweeps.
+ * Defaults to a full INT16 sweep; an emulated target (e.g. QEMU) can lower it
+ * to keep the run within its time budget. */
+#ifndef MAX_INTT_CONSTANT_COEFF
+#define MAX_INTT_CONSTANT_COEFF INT16_MAX
+#endif
+
 /* Declarations for _c functions exposed by MLK_STATIC_TESTABLE= */
 
 void mlk_poly_reduce_c(mlk_poly *r);
@@ -540,7 +547,7 @@ static int test_native_intt(void)
    *
    * Gradually increase absolute value to find smallest failure first.
    */
-  for (coeff = 0; coeff <= INT16_MAX; coeff++)
+  for (coeff = 0; coeff <= MAX_INTT_CONSTANT_COEFF; coeff++)
   {
     generate_i16_array_constant(test_data, MLKEM_N, (int16_t)coeff);
     CHECK(test_intt_core(test_data, "intt_constant") == 0);
@@ -1216,6 +1223,10 @@ static int test_poly_rej_uniform_consistency(void)
 
 
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(void);
+#endif
 int main(void)
 {
   /* WARNING: Test-only

test/wycheproof/wycheproof_mlkem.c

@@ -100,6 +100,10 @@ static void print_hex(const char *name, const unsigned char *raw, size_t len)
   printf("\n");
 }
 
+/* Prototype for a re-#define'd main, to satisfy -Wmissing-prototypes. */
+#if defined(main)
+int main(int argc, char *argv[]);
+#endif
 int main(int argc, char *argv[])
 {
   if (argc < 2)