Enhance: Add macos support

[jakerenzella]

A very early WIP to get compile-time DCC checks working on MacOS, as well as a working installation process.

Although Valgrind does not seem to support MacOS, therefore I am not sure how fruitful this endeavour may turn out to be, however compile-time explanations now work:

Potentially, usr/bin/leaks on MacOS could be used as a replacement for Valgrind, but would be a larger project

[jakerenzella]

@andrew-taylor Let me know what you think, mostly a PoC. If we disabled DCC run-time checks on MacOS we would have something that worked at compile-time.

[jakerenzella]

Not sure the proposed solution here ever worked: #42

[andrew-taylor]

If clang address & memory sanitizers work they potentially
could be run in tandem.
Memory sanitizer misses some error that valgrind catches but is useful.
Even if the address sanitizer run alone is very useful.
Could you try:

curl -sO https://raw.githubusercontent.com/COMP1511UNSW/dcc/master/tests/run_time_errors/illegal_malloc_array_index.c
clang -fsanitize-address illegal_malloc_array_index.c
a.out
curl -sO https://raw.githubusercontent.com/COMP1511UNSW/dcc/master/tests/run_time_errors/uninitialized-array-element-if.c
clang -fsanitize=memory uninitialized-array-element-if.c
a.out

[jakerenzella]

Apple's Clang:

• clang -fsanitize=address array_of_structs.c -o program 👍
• clang -fsanitize=leak array_of_structs.c -o program 👎
• clang -fsanitize=memory array_of_structs.c -o program 👎

llvm Clang via Brew:

• clang -fsanitize=address array_of_structs.c -o program 👍
• clang -fsanitize=leak array_of_structs.c -o program 👍
• clang -fsanitize=memory array_of_structs.c -o program 👎

[andrew-taylor]

merged indirectly - thanks!