File _multibuild of Package gcc15

<multibuild>
<flavor>gcc15-testresults</flavor>
<flavor>cross-aarch64-gcc15-bootstrap</flavor>
<flavor>cross-aarch64-gcc15</flavor>
<flavor>cross-loongarch64-gcc15-bootstrap</flavor>
<flavor>cross-loongarch64-gcc15</flavor>
<flavor>cross-riscv64-gcc15-bootstrap</flavor>
<flavor>cross-riscv64-gcc15</flavor>
<flavor>cross-s390x-gcc15-bootstrap</flavor>
<flavor>cross-s390x-gcc15</flavor>
<flavor>cross-ppc64le-gcc15-bootstrap</flavor>
<flavor>cross-ppc64le-gcc15</flavor>
<flavor>cross-hppa-gcc15-bootstrap</flavor>
<flavor>cross-hppa-gcc15</flavor>
<flavor>cross-arm-gcc15</flavor>
<flavor>cross-avr-gcc15-bootstrap</flavor>
<flavor>cross-avr-gcc15</flavor>
<flavor>cross-pru-gcc15-bootstrap</flavor>
<flavor>cross-pru-gcc15</flavor>
<flavor>cross-x86_64-gcc15</flavor>
<flavor>cross-sparc-gcc15</flavor>
<flavor>cross-sparc64-gcc15</flavor>
<flavor>cross-ppc64-gcc15</flavor>
<flavor>cross-m68k-gcc15</flavor>
<flavor>cross-mips-gcc15</flavor>
<flavor>cross-arm-none-gcc15-bootstrap</flavor>
<flavor>cross-arm-none-gcc15</flavor>
<flavor>cross-riscv64-elf-gcc15-bootstrap</flavor>
<flavor>cross-riscv64-elf-gcc15</flavor>
<flavor>cross-rx-gcc15-bootstrap</flavor>
<flavor>cross-rx-gcc15</flavor>
<flavor>cross-nvptx-gcc15</flavor>
<flavor>cross-amdgcn-gcc15</flavor>
<flavor>cross-bpf-gcc15</flavor>
</multibuild>