Document missing dependencies on Fedora, Debian

[xal-0]

Red Hat-based distros don't include the static version of libstdc++ in their g++ packages, so document this dependency, as well as the USE_RT_STATIC_LIBSTDCXX=0 workaround if it isn't available. I also looked for missing dependencies by compiling Julia in the base fedora:42 and debian:12 images:

FROM debian:12 AS build

ENV DEBIAN_FRONTEND=noninteractive
RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential libatomic1 python3 gfortran perl wget m4 cmake pkg-config \
    curl git ca-certificates

WORKDIR /build
RUN git clone --depth=1 https://github.com/JuliaLang/julia.git

RUN cd julia && make -j binary-dist VERBOSE=1

FROM fedora:42 AS build

RUN dnf install -y --nodocs --setopt=install_weak_deps=False \
    gcc gcc-c++ gcc-gfortran python3 perl wget m4 cmake pkgconfig curl git \
    which diffutils libatomic libstdc++-static

WORKDIR /build
RUN git clone --depth=1 https://github.com/JuliaLang/julia.git

RUN cd julia && make -j binary-dist VERBOSE=1

Reported by #60248 (comment).

[gbaraldi]

Can't we bundle this ourselves?

[xal-0]

I don't think it makes sense to ship static libstdc++ unless we also provide the compiler, since it is g++-version specific (unlike the dynamic library).

[gbaraldi]

Is this Gcc specific or does clang not provide a way to statically link libstdc++ at all?