[PATCH 3/3] shared/gatt-helpers: fix -std=c23 build failure

[Rudi Heitbaum <rudi@heitbaum.com>]

gcc-15 switched to -std=c23 by default:

    https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=55e3bd376b2214e200fa76d12b67ff259b06c212

As a result `bluez` fails the build as:

    src/shared/gatt-helpers.c:1136:24: error: incompatible types when returning type '_Bool' but 'struct bt_gatt_request *' was expected
     1136 |                 return false;
          |                        ^~~~~
    src/shared/gatt-helpers.c:1250:24: error: incompatible types when returning type '_Bool' but 'struct bt_gatt_request *' was expected
     1250 |                 return false;
          |                        ^~~~~
    src/shared/gatt-helpers.c:1478:24: error: incompatible types when returning type '_Bool' but 'struct bt_gatt_request *' was expected
     1478 |                 return false;
          |                        ^~~~~

Signed-off-by: Rudi Heitbaum <rudi@heitbaum.com>
---
 src/shared/gatt-helpers.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/shared/gatt-helpers.c b/src/shared/gatt-helpers.c
index 50fcb269b..f1fa6300a 100644
--- a/src/shared/gatt-helpers.c
+++ b/src/shared/gatt-helpers.c
@@ -1133,7 +1133,7 @@ struct bt_gatt_request *bt_gatt_discover_included_services(struct bt_att *att,
 	uint8_t pdu[6];
 
 	if (!att)
-		return false;
+		return NULL;
 
 	op = new0(struct bt_gatt_request, 1);
 	op->att = att;
@@ -1247,7 +1247,7 @@ struct bt_gatt_request *bt_gatt_discover_characteristics(struct bt_att *att,
 	uint8_t pdu[6];
 
 	if (!att)
-		return false;
+		return NULL;
 
 	op = new0(struct bt_gatt_request, 1);
 	op->att = att;
@@ -1475,7 +1475,7 @@ struct bt_gatt_request *bt_gatt_discover_descriptors(struct bt_att *att,
 	uint8_t pdu[4];
 
 	if (!att)
-		return false;
+		return NULL;
 
 	op = new0(struct bt_gatt_request, 1);
 	op->att = att;
-- 
2.43.0