[zaniebot]

CPython's BOLT rules optimize the build-tree binaries that make install copies into the installation, including shared libpython support from python#104709. The separate installation binaries introduced by #48 would otherwise be installed without BOLT optimization. Those binaries need different runtime library paths because an installed-layout DT_RPATH can override the build tree's intended libpython on glibc.

PBS's build script builds and installs CPython before rewriting the installed ELF library paths with patchelf. When BOLT is enabled, this edits an already optimized binary without relinking it, so no separately linked installation binary needs BOLT optimization. The downstream draft astral-sh/python-build-standalone#861 adopts separate installation binaries and includes the additional BOLT profile application for them.

Allow --enable-bolt with --enable-relocatable by applying the build-tree profiles to the installation counterparts, which are linked from the same object files. Collecting profiles with the build-tree binaries uses their build-time library lookup and avoids a second training run. Optimize installation libraries before the interpreter so their newer timestamps do not cause installation to relink the interpreter and discard its BOLT output. Refresh the shared-library alias only when BOLT optimized that library, and include installation copies in .prebolt cleanup.

This extends BOLT to the additional link outputs required by #48. The #49 alternative uses DT_RUNPATH and shares build and installation binaries, so it uses the ordinary BOLT rules.

Stacked on #48.