Fix missing-prototype errors in tests/suites

Signed-off-by: Michael Schuster <michael@schuster.ms>
diff --git a/tests/suites/main_test.function b/tests/suites/main_test.function
index f327a03..c0cc2ac 100644
--- a/tests/suites/main_test.function
+++ b/tests/suites/main_test.function
@@ -69,7 +69,7 @@
  *
  * \return       0 if exp_id is found. 1 otherwise.
  */
-int get_expression(int32_t exp_id, intmax_t *out_value)
+static int get_expression(int32_t exp_id, intmax_t *out_value)
 {
     int ret = KEY_VALUE_MAPPING_FOUND;
 
@@ -100,7 +100,7 @@
  *
  * \return       DEPENDENCY_SUPPORTED if set else DEPENDENCY_NOT_SUPPORTED
  */
-int dep_check(int dep_id)
+static int dep_check(int dep_id)
 {
     int ret = DEPENDENCY_NOT_SUPPORTED;
 
@@ -155,7 +155,7 @@
  *               DISPATCH_TEST_FN_NOT_FOUND if not found
  *               DISPATCH_UNSUPPORTED_SUITE if not compile time enabled.
  */
-int dispatch_test(size_t func_idx, void **params)
+static int dispatch_test(size_t func_idx, void **params)
 {
     int ret = DISPATCH_TEST_SUCCESS;
     TestWrapper_t fp = NULL;
@@ -193,7 +193,7 @@
  *               DISPATCH_TEST_FN_NOT_FOUND if not found
  *               DISPATCH_UNSUPPORTED_SUITE if not compile time enabled.
  */
-int check_test(size_t func_idx)
+static int check_test(size_t func_idx)
 {
     int ret = DISPATCH_TEST_SUCCESS;
     TestWrapper_t fp = NULL;