For the Clang compiler to work properly (at least the latest version), one needs to modify file cs_auto_flags.sh, line 400 which reads:
cflags_default="-funsigned-char -Wall -Wshadow -Wpointer-arith -Wmissing-prototypes -Wuninitialized -Wunused"
and change it to:
cflags_default="-funsigned-char -Wall -Wshadow -Wpointer-arith -Wmissing-prototypes -Wuninitialized -Wunused -Wno-incompatible-function-pointer-types -Wno-implicit-int"
in order to avoid warnings of "incompatible function pointer types" and "implicit integer" to be marked as errors. Otherwise, one should update the source code to fix these warnings.