segfault during unit tests on ppc64le and loongarch64

# Steps to Reproduce

On Alpine on `ppc64le` or `loongarch64` using the source from the tag `7.0` run:

```sh
sudo apk add cjson-dev cmake qt6-qtbase-dev samurai
cmake -B build -G Ninja -Wno-dev \
-DCMAKE_BUILD_TYPE=MinSizeRel \
-DCMAKE_INSTALL_PREFIX=/usr \
-DBUILD_SHARED_LIBS=ON \
-DBUILD_TOOLS=ON \
-DBUILD_TESTING=ON \
#
cmake --build build
```

# Expected Results

The unit tests pass

# Actual Result

## ppc64le

```
Test project /builds/maribu/aports/community/tinycbor/src/tinycbor-7.0/build
Start 1: tst_c90
Start 2: tst_cpp
Start 3: tst_encoder
Start 4: tst_parser
Start 5: tst_tojson
1/5 Test #1: tst_c90 .......................... Passed 0.01 sec
2/5 Test #2: tst_cpp .......................... Passed 0.01 sec
3/5 Test #4: tst_parser .......................***Exception: SegFault 0.01 sec
********* Start testing of tst_Parser *********
Config: Using QtTest library 6.11.0, Qt 6.11.0 (power64-little_endian-lp64 shared (dynamic) release build; by GCC 15.2.0), alpine 3.21.0_alpha20240923
PASS : tst_Parser::initTestCase()
PASS : tst_Parser::initParserEmpty()
Received signal 11 (SIGSEGV), code SEGV_ACCERR, accessing address 0x00007fffa50b0fff
integers function time: 0ms, total time: 1ms
4/5 Test #5: tst_tojson ....................... Passed 0.03 sec
5/5 Test #3: tst_encoder ...................... Passed 0.07 sec
80% tests passed, 1 tests failed out of 5
Total Test time (real) = 0.07 sec
The following tests FAILED:
4 - tst_parser (SEGFAULT)
Errors while running CTest
```

(Excerpt from [the full CI build log](https://gitlab.alpinelinux.org/maribu/aports/-/jobs/2311017).)

## loongarch64

```
Test project /builds/maribu/aports/community/tinycbor/src/tinycbor-7.0/build
Start 1: tst_c90
Start 2: tst_cpp
Start 3: tst_encoder
Start 4: tst_parser
Start 5: tst_tojson
1/5 Test #1: tst_c90 .......................... Passed 0.01 sec
2/5 Test #2: tst_cpp .......................... Passed 0.01 sec
3/5 Test #4: tst_parser .......................***Exception: SegFault 0.02 sec
********* Start testing of tst_Parser *********
Config: Using QtTest library 6.11.0, Qt 6.11.0 (loongarch64-little_endian-lp64 shared (dynamic) release build; by GCC 15.2.0), alpine 3.21.0_alpha20240923
PASS : tst_Parser::initTestCase()
PASS : tst_Parser::initParserEmpty()
Received signal 11 (SIGSEGV), code SEGV_ACCERR, accessing address 0x00007ffff23b8fff
integers function time: 0ms, total time: 1ms
4/5 Test #5: tst_tojson ....................... Passed 0.04 sec
5/5 Test #3: tst_encoder ...................... Passed 0.13 sec
80% tests passed, 1 tests failed out of 5
Total Test time (real) = 0.13 sec
The following tests FAILED:
4 - tst_parser (SEGFAULT)
Errors while running CTest
```

(Excerpt from [the full CI build log](https://gitlab.alpinelinux.org/maribu/aports/-/jobs/2311016).)