jit: Remove {llvm-config,clang}-N configure probes.

Previously we searched for llvm-config-N and clang-N as well as the
unversioned names, and maintained a list of expected values of N.  There
doesn't seem to be any reason to think that the default llvm-config and
clang won't be good enough, and if they aren't, they can be overridden
with LLVM_CONFIG and CLANG, so let's stop maintaining that list.

The list had not been updated since LLVM 7 with no complaints, so commit
820b5af probably should have just removed it when dropping support
for 7, instead of trying to be helpful by bringing it up to date with
recent version numbers.

The Meson build system didn't have that, so no change there.

Suggested-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CA%2BhUKG%2BSOP-aR%3DYF_n0dtXGWeCy6x%2BCn-RMWURU5ySQdmeKW1Q%40mail.gmail.com

Author: macdice

config/llvm.m4

@@ -13,7 +13,7 @@ AC_DEFUN([PGAC_LLVM_SUPPORT],
   AC_REQUIRE([AC_PROG_AWK])
 
   AC_ARG_VAR(LLVM_CONFIG, [path to llvm-config command])
-  PGAC_PATH_PROGS(LLVM_CONFIG, llvm-config llvm-config-17 llvm-config-16 llvm-config-15 llvm-config-14 llvm-config-13 llvm-config-12 llvm-config-11 llvm-config-10)
+  PGAC_PATH_PROGS(LLVM_CONFIG, llvm-config)
 
   # no point continuing if llvm wasn't found
   if test -z "$LLVM_CONFIG"; then
@@ -32,7 +32,7 @@ AC_DEFUN([PGAC_LLVM_SUPPORT],
 
   # need clang to create some bitcode files
   AC_ARG_VAR(CLANG, [path to clang compiler to generate bitcode])
-  PGAC_PATH_PROGS(CLANG, clang clang-17 clang-16 clang-15 clang-14 clang-13 clang-12 clang-11 clang-10)
+  PGAC_PATH_PROGS(CLANG, clang)
   if test -z "$CLANG"; then
     AC_MSG_ERROR([clang not found, but required when compiling --with-llvm, specify with CLANG=])
   fi

configure

@@ -5065,7 +5065,7 @@ if test "$with_llvm" = yes; then :
 
 
   if test -z "$LLVM_CONFIG"; then
-  for ac_prog in llvm-config llvm-config-17 llvm-config-16 llvm-config-15 llvm-config-14 llvm-config-13 llvm-config-12 llvm-config-11 llvm-config-10
+  for ac_prog in llvm-config
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -5138,7 +5138,7 @@ $as_echo "$as_me: using llvm $pgac_llvm_version" >&6;}
   # need clang to create some bitcode files
 
   if test -z "$CLANG"; then
-  for ac_prog in clang clang-17 clang-16 clang-15 clang-14 clang-13 clang-12 clang-11 clang-10
+  for ac_prog in clang
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2