fix aarch64 build proposal

[devnexen]

No description provided.

[kaniini]

Fix it on what?

[imnotpoz]

I just hit a build error with 1.3.3 from nixpkgs on aarch64-linux:

$ nix build nixpkgs#libucontext
error: Cannot build '/nix/store/bl0x379jvianpy6y3x8da1mawghmk02x-libucontext-1.3.3.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/6pyiqb4kdmqfq15lnr0cz864pbj4xxzy-libucontext-1.3.3
       Last 25 log lines:
       > build flags: -j5
       > [1/21] Compiling C object libucontext.so.1.p/arch_aarch64_swapcontext.S.o
       > [2/21] Compiling C object libucontext.so.1.p/arch_aarch64_setcontext.S.o
       > [3/21] Compiling C object libucontext.so.1.p/arch_aarch64_getcontext.S.o
       > [4/21] Compiling C object libucontext_posix.so.1.p/arch_aarch64_getcontext.S.o
       > [5/21] Compiling C object libucontext_posix.so.1.p/arch_aarch64_setcontext.S.o
       > [6/21] Compiling C object libucontext_posix.so.1.p/arch_aarch64_swapcontext.S.o
       > [7/21] Compiling C object libucontext.so.1.p/arch_aarch64_makecontext.c.o
       > FAILED: [code=1] libucontext.so.1.p/arch_aarch64_makecontext.c.o
       > gcc -Ilibucontext.so.1.p -I. -I.. -I../include -I../arch/common -I../arch/common/include -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu11 -fPIC -D_DEFAULT_SOURCE -DEXPORT_UNPREFIXED -MD -MQ libucontext.so.1.p/arch_aarch64_makecontext.c.o -MF libucontext.so.1.p/arch_aarch64_makecontext.c.o.d -o libucontext.so.1.p/arch_aarch64_makecontext.c.o -c ../arch/aarch64/makecontext.c
       > ../arch/aarch64/makecontext.c: In function 'libucontext_makecontext':
       > ../arch/aarch64/makecontext.c:48:14: error: assignment to 'long unsigned int *' from incompatible pointer type 'long long unsigned int *' [-Wincompatible-pointer-types]
       >    48 |         regp = &(ucp->uc_mcontext.regs[0]);
       >       |              ^
       > [8/21] Compiling C object libucontext.so.1.p/arch_aarch64_trampoline.c.o
       > [9/21] Compiling C object libucontext_posix.so.1.p/arch_aarch64_makecontext.c.o
       > FAILED: [code=1] libucontext_posix.so.1.p/arch_aarch64_makecontext.c.o
       > gcc -Ilibucontext_posix.so.1.p -I. -I.. -I../include -I../arch/common -I../arch/common/include -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu11 -fPIC -D_DEFAULT_SOURCE -DEXPORT_UNPREFIXED -MD -MQ libucontext_posix.so.1.p/arch_aarch64_makecontext.c.o -MF libucontext_posix.so.1.p/arch_aarch64_makecontext.c.o.d -o libucontext_posix.so.1.p/arch_aarch64_makecontext.c.o -c ../arch/aarch64/makecontext.c
       > ../arch/aarch64/makecontext.c: In function 'libucontext_makecontext':
       > ../arch/aarch64/makecontext.c:48:14: error: assignment to 'long unsigned int *' from incompatible pointer type 'long long unsigned int *' [-Wincompatible-pointer-types]
       >    48 |         regp = &(ucp->uc_mcontext.regs[0]);
       >       |              ^
       > [10/21] Compiling C object libucontext_posix.so.1.p/libucontext_posix.c.o
       > [11/21] Compiling C object libucontext_posix.so.1.p/arch_aarch64_trampoline.c.o
       > ninja: build stopped: subcommand failed.
       For full logs, run:
         nix log /nix/store/bl0x379jvianpy6y3x8da1mawghmk02x-libucontext-1.3.3.drv

I'm pretty sure this is what this PR is aiming to fix

[imnotpoz]

can confirm the changes to libucontext_mcontext_t in this PR match what's present in mcontext_t in glibc 2.40.66 on my system

[devnexen]

Hi @kaniini sorry for late reply, this is what @imnotpoz mentioned, I stumbled across this while testing on my raspberry at the time.