Given following log snippets, their explanation, and nothing else, explain what failure, if any, occurred during build of this package.

  Snippets are in a format of [X] : [Y], where [X] is a log snippet, and [Y] is the explanation.

  Snippets are delimited with '================'.

  Drawing on information from all snippets, provide a concise explanation of the issue and recommend a solution.

  Explanation of the issue, and recommended solution, should take a handful of sentences.

  Snippets:

  [gmake[2]: *** [vendor/CMakeFiles/libadb.dir/build.make:78: vendor/app_processes.pb.h] Error 1]: [Build has failed on line 78 of the `vendor/CMakeFiles/libadb.dir/build.make` while working with `vendor/app_processes.pb.h` source file, with code 1.]
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[gmake[1]: *** Waiting for unfinished jobs.]: [Unfinished jobs of the build are still continuing. ]
=============
[gmake: *** [Makefile:159: all] Error 2]: [Program `gmake` exited with code 2, indicating error. This happened while working on target `all` in the file `Makefile` on line 159.]
=============
[ # /usr/bin/systemd-nspawn -q -M 971615ef9ea540b5aab33085b8645de6 -D /var/lib/mock/rhel+epel-9-x86_64-1741087988.628519/root -a -u mockbuild --capability=cap_ipc_lock --rlimit=RLIMIT_NOFILE=10240 --capability=cap_ipc_lock --bind=/tmp/mock-resolv.1jxg69c3:/etc/resolv.conf --bind=/dev/btrfs-control --bind=/dev/mapper/control --bind=/dev/fuse --bind=/dev/loop-control --bind=/dev/loop0 --bind=/dev/loop1 --bind=/dev/loop2 --bind=/dev/loop3 --bind=/dev/loop4 --bind=/dev/loop5 --bind=/dev/loop6 --bind=/dev/loop7 --bind=/dev/loop8 --bind=/dev/loop9 --bind=/dev/loop10 --bind=/dev/loop11 --console=pipe --setenv=TERM=vt100 --setenv=SHELL=/bin/bash --setenv=HOME=/builddir --setenv=HOSTNAME=mock --setenv=PATH=/usr/bin:/bin:/usr/sbin:/sbin '--setenv=PROMPT_COMMAND=printf "\033]0;<mock-chroot>\007"' '--setenv=PS1=<mock-chroot> \s-\v\$ ' --setenv=LANG=C.UTF-8 --resolv-conf=off bash --login -c '/usr/bin/rpmbuild -bb  --target x86_64 --nodeps /builddir/build/originals/android-tools.spec']: [General error indicating build failure.]
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[app_processes.proto: This file contains proto3 optional fields, but --experimental_allow_proto3_optional was not set.]: [File `app_process.proto` contains proto3 optional fields, but flag allowing these fields `--experimental_allow_proto3_optional` was not set.]

Issue: File `app_process.proto` contained fields not supported by default flags used for build.
Resolution: Rerun the build with appropriate flags set, or make sure that all source files contain only supported features. In this case `app_process.proto` contained fields that are only supported by `--experimental_allow_proto3_optional` flag. Without it, the fields are not allowed.

Alternatively you can modify the file `app_process.proto` so it doesn't contain prohibited fields.