Organize dependencies

[gaborcsardi]

Manually built currently:

• gfortran (on x86_64, to add -fPIC), custom built on Alpine
• zlib (might not need manual build) We might be able to use the zlib-static package instead, and set up pkg-config to use that.
• openssl (might not need manual build) We might be able to use the openssl-libs-static package instead.
• libcurl
• xz Why not use the xz-static package instead?
• ncurses Use the ncurses-static package instead?
• readline Use the readline-static package?
• pcre2
• bzip2 (for -fPIC)
• openblas
• libpng (for -fPIC)
• libjpeg-turbo (for -fPIC)
• tiff (for -fPIC)
• util-linux
• fontconfig (for -fPIC)
• libffi (for -fPIC)
• gettext (for -fPIC)
• expat (for -fPIC)
• pango

Installed from Alpine

• icu (del dyn libs)
• libdeflate (del dyn libs)
• cairo (del dyn libs)
• harfbuzz
• fribidi
• pixman
• libxml2
• freetype
• brotli
• graphite2
• glib-static

[gaborcsardi]

Initially we can have a -libs image with all the dependencies installed, as needed for the R build.

At some point we will want to have individual packages, otherwise building the -libs image takes a long time, making upgrade of dependency versions harder.

We can build Alpine packages, by modifying the original Alpine APKBUILD files.

One question is whether we should install them at /usr or /usr/local. The latter is better if we want to share the libs with the glibc builds. But then we cannot install libs from stock Alpine, because they install at /usr. So we would need to build everything ourselves. Probably OK, because we are building almost everything already.