build: Alpine portability issues #32512
Description
Currently, when building on Alpine Linux, the build might fail in the following ways:
x86_64 && aarch64
/bitcoin/depends/work/build/x86_64-pc-linux-musl/native_capnp/1.1.0-725f3670538/src/kj/mutex.c++:37:10: fatal error: linux/futex.h: No such file or directory
37 | #include <linux/futex.h>
| ^~~~~~~~~~~~~~~
compilation terminated./bitcoin/depends/work/build/x86_64-pc-linux-musl/qt/6.7.3-be399392c6d/qtbase/src/corelib/io/qfilesystemengine_unix.cpp:64:12: fatal error: linux/fs.h: No such file or directory
64 | # include <linux/fs.h>
| ^~~~~~~~~~~~
compilation terminated./bitcoin/src/common/netif.cpp:16:10: fatal error: linux/rtnetlink.h: No such file or directory
16 | #include <linux/rtnetlink.h>
| ^~~~~~~~~~~~~~~~~~~aarch64
/bitcoin/src/crypto/sha256.cpp:19:10: fatal error: asm/hwcap.h: No such file or directory
19 | #include <asm/hwcap.h>
| ^~~~~~~~~~~~~
compilation terminated.These are all due to missinglinux-headers (which are not installed by default). They can be installed with apk add linux-headers.
We don't currently have any Alpine build docs, so they could be added, with a note about needing the headers being required, or, the code could be changed.