lint: Add README.mcld file.
Fix include style.
Fix zlib build dependencies.
Relocator: remove an unused argument in partialScanRelocation
debug info: Do not merge the debug string when doing partial linking
SymbolCategory: Fix regularEnd
[backend] Add section merge hooks.

Add section merge hooks so that the target linker backend
can do extra work before and after merging the input sections.
[arm] Override pre/post merge hooks.
[arm] Add exidx compress document.
[adt] Add ilist sort function.

This is a merge sort function for llvm::iplist.  There's the
benchmark numbers compared with the simple version in RelocData:

N           New (ns)        Orig (ns)       Delta           Speedup
----------  --------------  --------------  --------------  -------
       100          20,567          38,643          18,076   87.89%
       200          25,228          41,203          15,975   63.32%
       400          21,289          33,079          11,790   55.38%
       800          45,947          70,186          24,239   52.75%
     1,600         101,670         154,173          52,503   51.64%
     3,200         224,203         339,430         115,227   51.39%
     6,400         490,420         747,736         257,316   52.47%
    12,800       1,083,517       1,685,009         601,492   55.51%
    25,600       2,428,749       3,717,890       1,289,141   53.08%
    51,200       5,404,996       8,083,796       2,678,800   49.56%
   102,400      12,054,419      18,564,758       6,510,339   54.01%
   204,800      26,401,847      54,350,213      27,948,366  105.86%
   409,600      63,522,505     152,336,056      88,813,551  139.81%
   819,200     158,127,245     378,666,469     220,539,224  139.47%
 1,638,400     452,578,017   1,012,562,244     559,984,227  123.73%
 3,276,800   1,124,623,063   2,390,671,505   1,266,048,442  112.58%
 6,553,600   2,721,962,429   5,484,693,667   2,762,731,238  101.50%
13,107,200   6,434,574,826  12,383,973,961   5,949,399,135   92.46%
26,214,400  14,848,220,894  27,525,292,010  12,677,071,116   85.38%
[ld] Use better sort functionn to sort RelocData.
[arm] Add exception table data structure.
[object] Move postMergeSections hook.
[wip] relax.