(see commit msg for rationale and background).
To test, one should be able to use the cmake options such as -DCMAKE_C_COMPILER='clang' -DCMAKE_CXX_COMPILER='clang++' --preset=dev-mode -DBUILD_GUI=ON -DSANITIZERS=address on e.g. Fedora. Then see that the current suppressions file is insufficient, and also confirm that print_suppressions=0 is required.
The print_suppressions=0 is required to avoid a CI failure when the
suppressions were used. E.g:
```
$ LSAN_OPTIONS="suppressions=$(pwd)/test/sanitizer_suppressions/lsan:print_suppressions=1" ./bld-cmake/test/functional/interface_gui.py
2026-08-08T10:53:45.864160Z TestFramework (INFO): PRNG seed is: 8358096631255493262
2026-08-08T10:53:45.914748Z TestFramework (INFO): Initializing test directory /tmp/bitcoin_func_test_5zx5343v
2026-08-08T10:53:47.029997Z TestFramework (INFO): Test that bitcoin-gui starts up and can be stopped via RPC
2026-08-08T10:53:47.431761Z TestFramework (ERROR): Unexpected exception:
File "./test/functional/test_framework/test_node.py", line 534, in is_node_stopped
raise AssertionError("Unexpected stderr {} != {}".format(stderr, expected_stderr))
AssertionError: Unexpected stderr -----------------------------------------------------
Suppressions used:
count bytes template
2 181 bitcoin-qt
----------------------------------------------------- !=
```
The general suppression of the qt executables is required to avoid CI
failures for i386 builds. E.g:
```
test 2026-08-05T08:54:08.370427Z TestFramework (ERROR): Unexpected exception:
Traceback (most recent call last):
File "/ci_container_base/ci/scratch_ ₿🧪_/build-i686-pc-linux-gnu/test/functional/interface_gui.py", line 34, in run_test
self.stop_node(0)
~~~~~~~~~~~~~~^^^
File "/ci_container_base/test/functional/test_framework/test_node.py", line 525, in is_node_stopped
assert return_code in expected_ret_code, self._node_msg(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: [node 0] Node returned unexpected exit code (1) vs ((0,)) when stopping
node0 stderr =================================================================
==73449==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 386 byte(s) in 17 object(s) allocated from:
#0 0x5df28a2d in malloc (/ci_container_base/ci/scratch_ ₿🧪_/build-i686-pc-linux-gnu/bin/bitcoin-qt+0x1d0da2d) (BuildId: 496a5df531df278fe395724ae917f266331b3f81)
#1 0xee03c1d1 (<unknown module>)
Indirect leak of 12 byte(s) in 1 object(s) allocated from:
#0 0x5df28a2d in malloc (/ci_container_base/ci/scratch_ ₿🧪_/build-i686-pc-linux-gnu/bin/bitcoin-qt+0x1d0da2d) (BuildId: 496a5df531df278fe395724ae917f266331b3f81)
#1 0xee03c1d1 (<unknown module>)
SUMMARY: AddressSanitizer: 398 byte(s) leaked in 18 allocation(s).
```
<!--e57a25ab6845829454e8d69fc972939a-->
The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.
<!--006a51241073e994b41acfe9ec718e94-->
For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35937.
<!--021abf342d371248e50ceaed478a90ca-->
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ACK fad9ab714b5512f204f75a94d8cc4fa164dd4061