Support building with -Werror=strict-prototypes / -Werror=old-style-definition

Unfortunately "-std=c99" is not sufficient to make gcc ignore code that
uses constructs of earlier C standards, which were abandoned in C99.

See https://lwn.net/ml/fedora-devel/Y1kvF35WozzGBpc8@redhat.com/ for
some related discussion.

Change-Id: I84fd99442d0cc400fa562fa33623c142649230e2
diff --git a/tests/tlv/tlv_test.c b/tests/tlv/tlv_test.c
index fdd15ab..f9137ad 100644
--- a/tests/tlv/tlv_test.c
+++ b/tests/tlv/tlv_test.c
@@ -188,7 +188,7 @@
 	}
 }
 
-static void test_tlv_shift_functions()
+static void test_tlv_shift_functions(void)
 {
 	uint8_t test_data[1024];
 	uint8_t buf[1024];
@@ -250,7 +250,7 @@
 /* Most GSM related protocols clearly indicate that in case of duplicate
  * IEs, only the first occurrence shall be used, while any further occurrences
  * shall be ignored.  See e.g. 3GPP TS 24.008 Section 8.6.3 */
-static void test_tlv_repeated_ie()
+static void test_tlv_repeated_ie(void)
 {
 	uint8_t test_data[768];
 	int i, rc;
@@ -288,7 +288,7 @@
 	OSMO_ASSERT(dec3[2].lv[tag].val == &test_data[2 + 3 + 3]);
 }
 
-static void test_tlv_encoder()
+static void test_tlv_encoder(void)
 {
 	const uint8_t enc_ies[] = {
 		0x17, 0x14,	0x06, 0x2b, 0x12, 0x2b, 0x0b, 0x40, 0x2b, 0xb7, 0x05, 0xd0, 0x63, 0x82, 0x95, 0x03, 0x05, 0x40,
@@ -332,7 +332,7 @@
 	msgb_free(msg);
 }
 
-static void test_tlv_parser_bounds()
+static void test_tlv_parser_bounds(void)
 {
 	struct tlv_definition tdef;
 	struct tlv_parsed dec;
@@ -423,7 +423,7 @@
 	OSMO_ASSERT(TLVP_VAL(&dec, 0x23) == NULL);
 }
 
-static void test_tlv_lens()
+static void test_tlv_lens(void)
 {
 	uint16_t buf_len;
 	uint8_t buf[512];