Last commit before merging llvm_18

Merge pull request #38 from PearCoding/set_cache_dir

Allow user to replace and query default cache directory

Merge pull request #26 from AnyDSL/add-amdgcn_s_memrealtime

Add amdgcn_s_memrealtime()

Fix for iterator invalidation

Call ldd via system, fixes:

: CommandLine Error: Option 'asm-instrumentation' registered more than once!
LLVM ERROR: inconsistency in registered CommandLine options

oops: wrong branch