cmake mingw ignoring -Wl,--gc-sections

I have a problem with this code in C++:

void f();
void g()
{
    f();
}

f() is not defined anywhere in the project and g() is not called anywhere. I use the following cmake directives:

add_compile_options(-fdata-sections -ffunction-sections)
add_link_options(-Wl,--gc-sections)

Using mingw32 the linker complains that f() is missing, but that's not what I expect since g() should not be linked in the first place. Using gcc on linux the project links correctly. I suspect that mingw 1st creates an intermediate library. This is the verbose output

C:\msys64\mingw32\bin\g++.exe -g  -Wl,--gc-sections -Wl,--whole-archive CMakeFiles\main.dir/objects.a -Wl,--no-whole-archive  -o main.exe -Wl,--out-implib,libmain.dll.a -Wl,--major-image-version,0,--minor-image-version,0 @CMakeFiles\main.dir\linklibs.rsp
CMakeFiles\main.dir/objects.a(main.cpp.obj): In function `Z1gv':
C:/Users/Documents/Sandbox/testcmake/main.cpp:20: undefined reference to `f()'
collect2.exe: error: ld returned 1 exit status

--- EDIT ---

I can replicate the issue with this simple test:

main.cpp:

void f();

void g(){
        f();
}

int main(){
        return 0;
}

Then compile with:

gcc -o main main.cpp -fdata-sections -ffunction-sections -Wl,--gc-sections

In mingw32: undefined reference to `f()'

In linux: OK