precompiled releases include debug symbols

[dbernheisel]

binaries shipped in github releases contain debug symbols. Stripping them would reduce download and Docker image sizes with no impact on functionality.

Reproduction

FROM hexpm/elixir:1.19.5-erlang-28.3-debian-trixie-20260112-slim

RUN apt-get update -qq \
    && apt-get install -y -qq --no-install-recommends curl file binutils ca-certificates > /dev/null 2>&1

RUN mkdir -p /tmp/xla && cd /tmp/xla \
    && curl -sL -o xla.tar.gz \
       "https://github.com/elixir-nx/xla/releases/download/v0.9.1/xla_extension-0.9.1-x86_64-linux-gnu-cpu.tar.gz" \
    && tar xzf xla.tar.gz

RUN file /tmp/xla/xla_extension/lib/libxla_extension.so
# ELF 64-bit LSB shared object, x86-64, ..., not stripped
RUN strip /tmp/xla/xla_extension/lib/libxla_extension.so
RUN file /tmp/xla/xla_extension/lib/libxla_extension.so

the after is with strip libxla_extension.so

x86_64-linux-gnu-cpu (v0.9.1):

• before: 423 MB
• after: 324 MB
• saved: ~100 MB (24%)

aarch64-linux-gnu-cuda12 (v0.9.1):

• before: 470 MB
• after: 349 MB
• saved: ~121 MB (26%)

[polvalente]

I think we should have -debug builds with the debug info and default to the usual -O3

[cocoa-xu]

Or maybe we can also split and upload the debug symbols as a standalone file?

FROM hexpm/elixir:1.19.5-erlang-28.3-debian-trixie-20260112-slim

RUN apt-get update -qq \
    && apt-get install -y -qq --no-install-recommends curl file binutils ca-certificates > /dev/null 2>&1

RUN mkdir -p /tmp/xla && cd /tmp/xla \
    && curl -sL -o xla.tar.gz \
       "https://github.com/elixir-nx/xla/releases/download/v0.9.1/xla_extension-0.9.1-x86_64-linux-gnu-cpu.tar.gz" \
    && tar xzf xla.tar.gz

RUN file /tmp/xla/xla_extension/lib/libxla_extension.so
# ELF 64-bit LSB shared object, x86-64, ..., not stripped

# Save debug symbols
RUN objcopy --only-keep-debug /tmp/xla/xla_extension/lib/libxla_extension.so /tmp/xla/xla_extension/lib/libxla_extension.so.debug

# Strip debug symbols
RUN strip /tmp/xla/xla_extension/lib/libxla_extension.so

RUN file /tmp/xla/xla_extension/lib/libxla_extension.so
RUN file /tmp/xla/xla_extension/lib/libxla_extension.so.debug

[jonatanklosko]

We definitely want to avoid multiple builds with different flags.

Moving debug symbols into a separate .debug sounds reasonable. I think we could keep them in the same target .tar.gz archive. When building Elixir release, only the .so is actually copied over to the release priv.