pgsql: jit: Require at least LLVM 10.

jit: Require at least LLVM 10.

Remove support for older LLVM versions.  The default on common software
distributions will be at least LLVM 10 when PostgreSQL 17 ships.

Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CA%2BhUKGLhNs5geZaVNj2EJ79Dx9W8fyWUU3HxcpZy55sMGcY%3DiA%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/820b5af73dcc6a5d0db6a98a62a6b859e5d107b6

Modified Files
--------------
config/llvm.m4                          | 10 +++---
configure                               | 43 +++--------------------
doc/src/sgml/installation.sgml          |  4 +--
meson.build                             |  2 +-
src/backend/jit/llvm/llvmjit.c          | 57 ++----------------------------
src/backend/jit/llvm/llvmjit_error.cpp  | 10 ------
src/backend/jit/llvm/llvmjit_expr.c     |  6 +---
src/backend/jit/llvm/llvmjit_inline.cpp | 38 ++------------------
src/backend/jit/llvm/llvmjit_wrap.cpp   | 61 ---------------------------------
src/include/jit/llvmjit.h               | 17 ---------
src/include/pg_config.h.in              | 12 -------
11 files changed, 17 insertions(+), 243 deletions(-)