fix for #18: initializing comm memory

Static linking can be selected with -DSTATIC_LINKING:BOOL=ON

BCC API for attaching tracing events has been cleaned up - no more perf
readers

Store number of online CPUs, so we don't need to read /sys/devices/system/cpu/online while probes are running

e.g. kprobe:[Ss]y[Ss]_read { ... }

tracepoint:random:*_read { ... }
kprobe:sys_read, uprobe:/bin/bash:readline { ... }

Previously the auto-generated key type was the same as the value type,
which made maps containing string values use far more stack memory than
they should when accessing them.

Commit 3dd703a5 didn't fix it as intended

For count() maps, sort by value
For others, sort by key

BPF programs can't span multiple functions - add always inliner pass
so multiple calls to strcmp will work.

LLVM version-independent workaround from BCC

e.g. @x = "a"; @y = @x;