Failed to compile project with `-fwasm-exceptions` that uses objc exceptions

Please include the following in your bug report:

**Version of emscripten/emsdk:**
Please include the output `emcc -v` here
```yaml
frityet@fritpc:~/objfw-1.2.3$ emcc -v
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.74 (1092ec30a3fb1d46b1782ff1b4db5094d3d06ae5)
clang version 20.0.0git (https:/github.com/llvm/llvm-project 322eb1a92e6d4266184060346616fa0dbe39e731)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /emsdk/upstream/bin
```

(This is the latest, as of 25-01-12, version of the emscripten docker image)

**Failing command line in full:**
If this is compile or link-time failure please include the full failing command
along with its entire output.
```yaml
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0. Program arguments: /emsdk/upstream/bin/clang -target wasm32-unknown-emscripten -mno-bulk-memory -mno-bulk-memory-opt -mno-nontrapping-fptoint -mllvm -combiner-global-alias-analysis=false -mllvm -wasm-enable-sjlj -mllvm -disable-lsr --sysroot=/emsdk/upstream/emscripten/cache/sysroot -DEMSCRIPTEN -Werror=implicit-function-declaration -Xclang -iwithsysroot/include/fakesdl -Xclang -iwithsysroot/include/compat -fwasm-exceptions -Wall -fexceptions -fobjc-exceptions -funwind-tables -fconstant-string-class=OFConstantString -std=gnu11 -pipe -fno-common -Xclang -fno-constant-cfstrings -Wsign-compare -Wshadow -Wshorten-64-to-32 -Wundeclared-selector -Wsemicolon-before-method-body -Wobjc-missing-property-synthesis -Wmissing-method-return-type -Xclang -fobjc-runtime=objfw -Xclang -fblocks -Wwrite-strings -Wpointer-arith -Wcast-align -Wunreachable-code -Wdocumentation -pedantic -D_GNU_SOURCE -DOF_COMPILING_OBJFW -I. -I.. -I../.. -I../runtime -MD -MF OFAllocFailedException.dep -c OFAllocFailedException.m -o OFAllocFailedException.o
1. parser at end of file
2. Code generation
3. Running pass 'Function Pass Manager' on module 'OFAllocFailedException.m'.
4. Running pass 'WebAssembly Instruction Selection' on function '@_i_OFAllocFailedException__init'
#0 0x000055a2e4dfa888 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/emsdk/upstream/bin/clang+0x2ec6888)
#1 0x000055a2e4df7bee llvm::sys::RunSignalHandlers() (/emsdk/upstream/bin/clang+0x2ec3bee)
#2 0x000055a2e4df9adf llvm::sys::CleanupOnSignal(unsigned long) (/emsdk/upstream/bin/clang+0x2ec5adf)
#3 0x000055a2e4d5bac9 (/emsdk/upstream/bin/clang+0x2e27ac9)
#4 0x00007fec74242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#5 0x000055a2e61721b9 (/emsdk/upstream/bin/clang+0x423e1b9)
clang: error: clang frontend command failed with exit code 133 (use -v to see invocation)
clang version 20.0.0git (https:/github.com/llvm/llvm-project 322eb1a92e6d4266184060346616fa0dbe39e731)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /emsdk/upstream/bin
clang: note: diagnostic msg:
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/OFAllocFailedException-198e1c.m
clang: note: diagnostic msg: /tmp/OFAllocFailedException-198e1c.sh
clang: note: diagnostic msg:

********************
```

`/tmp/OFAllocFailedException-198e1c.m`: https://gist.github.com/Frityet/e37e28716f1e579acb77d829223d6817
`/tmp/OFAllocFailedException-198e1c.sh`:

```sh
# Crash reproducer for clang version 20.0.0git (https:/github.com/llvm/llvm-project 322eb1a92e6d4266184060346616fa0dbe39e731)
# Driver args: "-target" "wasm32-unknown-emscripten" "-mno-bulk-memory" "-mno-bulk-memory-opt" "-mno-nontrapping-fptoint" "-mllvm" "-combiner-global-alias-analysis=false" "-mllvm" "-wasm-enable-sjlj" "-mllvm" "-disable-lsr" "--sysroot=/emsdk/upstream/emscripten/cache/sysroot" "-D" "EMSCRIPTEN" "-Werror=implicit-function-declaration" "-Xclang" "-iwithsysroot/include/fakesdl" "-Xclang" "-iwithsysroot/include/compat" "-fwasm-exceptions" "-Wall" "-fexceptions" "-fobjc-exceptions" "-funwind-tables" "-fconstant-string-class=OFConstantString" "-std=gnu11" "-pipe" "-fno-common" "-Xclang" "-fno-constant-cfstrings" "-Wsign-compare" "-Wshadow" "-Wshorten-64-to-32" "-Wundeclared-selector" "-Wsemicolon-before-method-body" "-Wobjc-missing-property-synthesis" "-Wmissing-method-return-type" "-Xclang" "-fobjc-runtime=objfw" "-Xclang" "-fblocks" "-Wwrite-strings" "-Wpointer-arith" "-Wcast-align" "-Wunreachable-code" "-Wdocumentation" "-pedantic" "-D" "_GNU_SOURCE" "-D" "OF_COMPILING_OBJFW" "-I" "." "-I" ".." "-I" "../.." "-I" "../runtime" "-MD" "-MF" "OFAllocFailedException.dep" "-c" "OFAllocFailedException.m" "-o" "OFAllocFailedException.o"
# Original command: "/emsdk/upstream/bin/clang-20" "-cc1" "-triple" "wasm32-unknown-emscripten" "-emit-obj" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "OFAllocFailedException.m" "-mrelocation-model" "static" "-mframe-pointer=none" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=1" "-target-feature" "+exception-handling" "-mllvm" "-wasm-enable-eh" "-target-feature" "+multivalue" "-target-feature" "+reference-types" "-target-feature" "+exception-handling" "-exception-model=wasm" "-target-feature" "+multivalue" "-target-feature" "+reference-types" "-target-cpu" "generic" "-target-feature" "-bulk-memory" "-target-feature" "-bulk-memory-opt" "-target-feature" "-nontrapping-fptoint" "-fvisibility=hidden" "-debugger-tuning=gdb" "-fdebug-compilation-dir=/home/frityet/Boxes/emscripten/objfw-1.2.3/src/exceptions" "-fcoverage-compilation-dir=/home/frityet/Boxes/emscripten/objfw-1.2.3/src/exceptions" "-resource-dir" "/emsdk/upstream/lib/clang/20" "-dependency-file" "OFAllocFailedException.dep" "-MT" "OFAllocFailedException.o" "-sys-header-deps" "-D" "EMSCRIPTEN" "-D" "_GNU_SOURCE" "-D" "OF_COMPILING_OBJFW" "-I" "." "-I" ".." "-I" "../.." "-I" "../runtime" "-isysroot" "/emsdk/upstream/emscripten/cache/sysroot" "-internal-isystem" "/emsdk/upstream/lib/clang/20/include" "-internal-isystem" "/emsdk/upstream/emscripten/cache/sysroot/include/wasm32-emscripten" "-internal-isystem" "/emsdk/upstream/emscripten/cache/sysroot/include" "-Werror=implicit-function-declaration" "-Wall" "-Wsign-compare" "-Wshadow" "-Wshorten-64-to-32" "-Wundeclared-selector" "-Wsemicolon-before-method-body" "-Wobjc-missing-property-synthesis" "-Wmissing-method-return-type" "-Wwrite-strings" "-Wpointer-arith" "-Wcast-align" "-Wunreachable-code" "-Wdocumentation" "-pedantic" "-std=gnu11" "-fconst-strings" "-fconstant-string-class" "OFConstantString" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fskip-odr-check-in-gmf" "-fobjc-runtime=gnustep" "-fobjc-encode-cxx-class-template-spec" "-fobjc-exceptions" "-fexceptions" "-exception-model=wasm" "-fcolor-diagnostics" "-iwithsysroot/include/fakesdl" "-iwithsysroot/include/compat" "-fno-constant-cfstrings" "-fobjc-runtime=objfw" "-fblocks" "-mllvm" "-combiner-global-alias-analysis=false" "-mllvm" "-wasm-enable-sjlj" "-mllvm" "-disable-lsr" "-o" "OFAllocFailedException.o" "-x" "objective-c" "OFAllocFailedException.m"
"/emsdk/upstream/bin/clang-20" "-cc1" "-triple" "wasm32-unknown-emscripten" "-emit-obj" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "OFAllocFailedException.m" "-mrelocation-model" "static" "-mframe-pointer=none" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=1" "-target-feature" "+exception-handling" "-mllvm" "-wasm-enable-eh" "-target-feature" "+multivalue" "-target-feature" "+reference-types" "-target-feature" "+exception-handling" "-exception-model=wasm" "-target-feature" "+multivalue" "-target-feature" "+reference-types" "-target-cpu" "generic" "-target-feature" "-bulk-memory" "-target-feature" "-bulk-memory-opt" "-target-feature" "-nontrapping-fptoint" "-fvisibility=hidden" "-debugger-tuning=gdb" "-fdebug-compilation-dir=/home/frityet/Boxes/emscripten/objfw-1.2.3/src/exceptions" "-fcoverage-compilation-dir=/home/frityet/Boxes/emscripten/objfw-1.2.3/src/exceptions" "-sys-header-deps" "-D" "EMSCRIPTEN" "-D" "_GNU_SOURCE" "-D" "OF_COMPILING_OBJFW" "-Werror=implicit-function-declaration" "-Wall" "-Wsign-compare" "-Wshadow" "-Wshorten-64-to-32" "-Wundeclared-selector" "-Wsemicolon-before-method-body" "-Wobjc-missing-property-synthesis" "-Wmissing-method-return-type" "-Wwrite-strings" "-Wpointer-arith" "-Wcast-align" "-Wunreachable-code" "-Wdocumentation" "-pedantic" "-std=gnu11" "-fconst-strings" "-fconstant-string-class" "OFConstantString" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fskip-odr-check-in-gmf" "-fobjc-runtime=gnustep" "-fobjc-encode-cxx-class-template-spec" "-fobjc-exceptions" "-fexceptions" "-exception-model=wasm" "-fcolor-diagnostics" "-iwithsysroot/include/fakesdl" "-iwithsysroot/include/compat" "-fno-constant-cfstrings" "-fobjc-runtime=objfw" "-fblocks" "-mllvm" "-combiner-global-alias-analysis=false" "-mllvm" "-wasm-enable-sjlj" "-mllvm" "-disable-lsr" "-x" "objective-c" "OFAllocFailedException-198e1c.m"
```

Same result also occurs with emscripten running on macOS 13
```yaml
❯ sw_vers
ProductName: macOS
ProductVersion: 13.6.7
BuildVersion: 22G720
❯ emcc -v
emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.74-git
clang version 20.0.0git
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /usr/local/Cellar/emscripten/3.1.74/libexec/llvm/bin
```