make map stack indentation 4 chars

Prevent empty trigger functions to be optimized away with -O2 (#218)

From the gcc manual: 'noinline - This function attribute prevents a
function from being considered for inlining. If the function does not
have side effects, there are optimizations other than inlining that
cause function calls to be optimized away, although the function call is
live. To keep such calls from being optimized away, put asm ("");'
(https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html)

-D__BPF_TRACING__

I was trying bpftrace on my example[1] with updated kernel (4.19.16) and
got:

	/lib/modules/4.19.0-2-amd64/source/arch/x86/include/asm/cpufeature.h:150:2: warning: "Compiler lacks ASM_GOTO support. Add -D __BPF_TRACING__ to your compiler arguments" [-W#warnings]

This was added in https://git.kernel.org/linus/b1ae32dbab which also
adds -D__BPF_TRACING__ to samples/bpf/Makefile in kernel.

[1] https://github.com/iovisor/bpftrace/issues/252#issuecomment-440346608

Re-enable subset of build warnings and fix some related warnings #316

Cleanup enforce_infinite_rlimits

Add support for arm64 (aarch64)

: removed getrlimit()
: Added error description using strerror()
Signed-off-by: T K Sourab <sourabhtk37@gmail.com>

Fixes issue #338

probe type aliases don't work with -l

follow the new libbcc interface: bcc_{create_map, prog_load}

all abort()s should print an error message

libbcc has renamed the following API recently (see bcc pr#2149):

    bpf_create_map  =>  bcc_create_map
    bpf_prog_load   =>  bcc_prog_load

Let's use the new API whenever possible and fall back to the old otherwise.

This patch fixes the docker builds (`./build.sh` and
`./build-debug.sh`).

Two main things were broken:
* Alpine was missing a bcc-devel package. The temporary fix is to clone
  bcc, build, and install into the container
* Static linking against bcc was broken. I've made some cmake config
  changes to support this.

Add support to list tracepoint arguments (#323)

ksym() alias/replacement to sym()

Lesson 9: Replace "stack" to "kstack".

Fix warning issue for Lesson 9: the stack is deprecated and will be removed in the future. Use kstack instead

kstack alias/replacement to stack 

fix tracepoint wildcards

cmake: add BUILD_TESTING support

Probe list optimizations and improvements

use structs with semicolons

- Moved regex init code outside search_probe function (avoiding to be
called again at every invocation)
- inlined search_probe function
- Added std::regex::optimize flag to regex
- Fixed search of "software*" and "hardware*"

Before:

time ./bpftrace -l '*xfs*'|wc -l
2363

real	0m1.841s
user	0m1.576s
sys	0m0.261s

After:

time ./bpftrace -l '*xfs*'|wc -l
2363

real	0m1.179s
user	0m0.904s
sys	0m0.271s

struct definitions that end with semicolons

If we use clang to build bpftrace instead of GCC, it will complain about
trying to use the `-std-c++14` flag to comile headers.c. If we force
cmake to skip this flag on `.c` files, clang is not able to link
libresources.a correctly.

This patch changes the resources workflow to generate a .cpp file
instead, and to have a `src/headers.h` with all headers we currently
use. With this approach we get a safer linkage because the same
definition for the header strings is being used in clang_parser.cpp and
in headers.cpp.

Fixes: https://github.com/iovisor/bpftrace/issues/350