Upgrade to 18

Makefile

@@ -3,10 +3,10 @@
 # to be set, but for the time being we need to override the defaults so that our existing dev environment works. This
 # can be removed when that is resolved.
 ifeq ($(CC),cc)
-CC = /usr/bin/clang
+CC = ccache /usr/bin/clang-18
 endif
 ifeq ($(CXX),g++)
-CXX = /usr/bin/clang++
+CXX = ccache /usr/bin/clang++-18
 endif
 
 # Set the optimization level from the environment, or default to -O2.
@@ -23,7 +23,7 @@ PROJECT = $(shell git rev-parse --show-toplevel)
 INCLUDE = -I$(PROJECT) -I$(PROJECT)/mbedtls/include
 
 # Set our standard C++ compiler flags
-CXXFLAGS = -g -std=c++20 -fPIC -DSQLITE_ENABLE_NORMALIZE $(BEDROCK_OPTIM_COMPILE_FLAG) -Werror -Wformat-security  -Wno-error=deprecated-declarations $(INCLUDE) #-Wall -Werror
+CXXFLAGS = -g -std=c++20 -stdlib=libc++ -I/usr/include/c++/v1 -fPIC -DSQLITE_ENABLE_NORMALIZE $(BEDROCK_OPTIM_COMPILE_FLAG) -Wno-vla-cxx-extension -Wno-unqualified-std-cast-call -Werror -Wformat-security  -Wno-error=deprecated-declarations $(INCLUDE) #-Wall -Werror
 
 # Amalgamation flags
 AMALGAMATION_FLAGS = -Wno-unused-const-variable -DSQLITE_ENABLE_FTS5 -DSQLITE_ENABLE_STAT4 -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_SESSION -DSQLITE_ENABLE_PREUPDATE_HOOK -DSQLITE_ENABLE_UPDATE_DELETE_LIMIT -DSQLITE_ENABLE_NOOP_UPDATE -DSQLITE_MUTEX_ALERT_MILLISECONDS=20 -DHAVE_USLEEP=1 -DSQLITE_MAX_MMAP_SIZE=17592186044416ull -DSQLITE_SHARED_MAPPING -DSQLITE_ENABLE_NORMALIZE -DSQLITE_MAX_PAGE_COUNT=4294967294 -DSQLITE_DISABLE_PAGECACHE_OVERFLOW_STATS
@@ -32,7 +32,7 @@ AMALGAMATION_FLAGS = -Wno-unused-const-variable -DSQLITE_ENABLE_FTS5 -DSQLITE_EN
 INTERMEDIATEDIR = .build
 
 # We use the same library paths and required libraries for all binaries.
-LIBPATHS =-L$(PROJECT) -Lmbedtls/library
+LIBPATHS =-L$(PROJECT) -Lmbedtls/library -L/usr/lib/llvm-18/lib
 LIBRARIES =-Wl,--start-group -lbedrock -lstuff -Wl,--end-group -ldl -lpcrecpp -lpthread -lmbedtls -lmbedx509 -lmbedcrypto -lz -lm
 
 # These targets aren't actual files.