Feature or enhancement

I have a stack of patches in #101093 to overhaul build system rules related to PGO and BOLT. This issue tracks the merging of them.

Roughly:

• gh-xxxx: inline minimal PGO rules to simplify Makefile
• gh-xxxx: overhaul build rules for profile optimized binaries
• gh-xxxx: various BOLT config changes
• gh-xxxx: enable BOLT of libpython (this is the one we care about)

I'm scope bloating myself to fix various bugs in PGO/BOLT as part of this refactor. For example, the build system today has a rather crude method of determining if a binary is PGO/BOLT instrumented or needs optimization. This set of changes will fix that so that proper dependencies in the make DAG capture the state of things.

Read the commit messages for the commits in #101093 to get a preview of what's to come.

Linked PRs

• gh-104523: inline minimal PGO rules #104524
• [WIP] gh-104523 overhaul build rules for optimized binaries #104525
• gh-104523: Use dynamic rule for compiling libmpdec and libexpat #104574