Basic CMake system (depends on #15)

[joneschrisg]

To create an Eclipse project that should be equivalent to the old one

cmake -G "Eclipse CDT4 - Unix Makefiles" .

To generate the default (just a Makefile)

cmake .

This commit also adds a helper "configure" script so that ./configure && make does the right thing.

I wasn't able to build the syscall wrapper library with this system. I see

/home/cjones/rr/rr/src/share/wrap_syscalls.c: In function ‘clock_gettime’:
/home/cjones/rr/rr/src/share/wrap_syscalls.c:290:2: error: inconsistent operand constraints in an ‘asm’

I'm not sure if this was already broken and disabled, or these commits broke something. Checking on that now.

[joneschrisg]

Sorry, forgot to update this yesterday. The build error was from incorrectly using $ebx in code compiled with -fPIC. After that was fixed, libc malloc started asserting early in startup. I've just established that that's (somehow) caused by the length or format of arguments on the command line. This command works with the Eclipse build but causes the assertion failure in the CMake build

./rr --record --filter_lib=../rr/obj/lib/librr_wrap_syscalls.so ./hello

However, this command works fine in the CMake build

./rr --record --filter_lib=/home/cjones/rr/rr/obj/lib/librr_wrap_syscalls.so ./hello

Smelling like a fencepost bug somewhere ...