Bug#995187: qtwebengine-opensource-src FTBFS on mips*: unistd_nr_{n32,n64,o32}.h no linger exported by the kernel

Source: qtwebengine-opensource-src
Version: 5.15.5+dfsg-2
Severity: serious
Tags: ftbfs

https://buildd.debian.org/status/fetch.php?pkg=qtwebengine-opensource-src&arch=mips64el&ver=5.15.6%2Bdfsg-1&stamp=1632387575&raw=0

...
FAILED: obj/sandbox/linux/seccomp_bpf/syscall_set.o
/usr/bin/g++ -MMD -MF obj/sandbox/linux/seccomp_bpf/syscall_set.o.d -DSANDBOX_IMPLEMENTATION -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DOPENSSL_NO_ASM -Igen -I../../3rdparty/chromium -I../../3rdparty/chromium/third_party/perfetto/include -Igen/third_party/perfetto/build_config -Igen/third_party/perfetto -Igen -Igen -Igen -Igen -I../../3rdparty/chromium/third_party/abseil-cpp -I../../3rdparty/chromium/third_party/boringssl/src/include -I../../3rdparty/chromium/third_party/protobuf/src -Igen/protoc_out -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -D__SANE_USERSPACE_TYPES__ -mips64r2 -Wa,-mips64r2 -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -O2 -fno-ident -fdata-sections -ffunction-sections -fno-omit-frame-pointer -g0 -fvisibility=hidden -std=gnu++14 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -fno-exceptions -fno-rtti -fvisibility-inlines-hidden -c ../../3rdparty/chromium/sandbox/linux/bpf_dsl/syscall_set.cc -o obj/sandbox/linux/seccomp_bpf/syscall_set.o
In file included from ../../3rdparty/chromium/sandbox/linux/bpf_dsl/syscall_set.cc:12:
../../3rdparty/chromium/sandbox/linux/bpf_dsl/linux_syscall_ranges.h:47:10: fatal error: asm/unistd_nr_n64.h: No such file or directory
   47 | #include <asm/unistd_nr_n64.h>  // for __NR_64_Linux and __NR_64_Linux_syscalls
      |          ^~~~~~~~~~~~~~~~~~~~~
compilation terminated.
...


Context:
https://sources.debian.org/src/qtwebengine-opensource-src/5.15.6+dfsg-1/debian/patches/mipsel-linux-5.patch/
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ccb21774863a