* rely less on the shell and more on GNU make to parse the versions
* fixed retrieval of minor version (for 18.1.8 it gave 8 instead of 1!)
* auto-detection of llvm-config within the supported version range
* replaced backticks by `$(...)` syntax
* tested against `busybox static-sh`, `bash`, `dash` and `csh`
Adjust version check to only warn for LLVM 17.x and newer, which are the
development versions. Otherwise we'll get:
```bash
make LLVM_CONFIG=llvm-config-15 CC=clang-15 CXX=clang++-15
<snip>
GNUmakefile.llvm:69: you are using an in-development llvm version - this might break llvm_mode!
```
for versions that are supported, and not in development.
- Lifting the standard to C++17.
- Beyond the cosmetic changes, it boils down to BasicBlock::getInstList being
no longer available (and reading the header it is no accident).
Building into a DESTDIR gives circular links such as:
lrwxrwxrwx. 1 rjones rjones 17 Mar 31 18:09 /home/rjones/rpmbuild/BUILDROOT/american-fuzzy-lop-4.00c-3.git285a5cb3.fc37.x86_64/usr/lib64/afl/afl-compiler-rt.o -> afl-compiler-rt.o
I have to admit I've no idea what the original link command is trying
to achieve, but it's clearly wrong and deleting it fixes the problem.
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
