BRANCH LuaJIT-2.1
x86: Remove x87 support from interpreter.

SSE2 required from now on.
x86/x64: Drop xmm register/memory move tuning for K8.
Add support for embedding LuaJIT bytecode for builtins.
Replace math.deg/math.rad with builtin Lua function.
Don't modify generated libbc header if unchanged.
Remove obsolete non-truncating number to integer conversions.
Add special bytecodes for builtins.

BC_ISTYPE, BC_ISNUM: fast type checks/coercions.
BC_TGETR, BC_TSETR: fast rawgeti/rawseti, no type checks for table/key.
Replace table.getn/foreach/foreachi with bytecode builtins.
Merge branch 'master' into v2.1
Fix genlibbc.
Replace table.remove with bytecode builtin.
Merge branch 'master' into v2.1
String buffer refactoring, part 1.

Move string buffer handling to lj_buf.*.
Use common buffer resizing function.
String buffer refactoring, part 2.

Switch to pointers for start/pos/end of buffer.
Abstract out some buffer writers.
Cleanup lexer source code.
String buffer refactoring, part 3.

Switch to pointers for start/end of buffer in lexer.
String buffer refactoring, part 4.

Add lua_State pointer to SBuf for buffer resizing.
Merge branch 'master' into v2.1
Merge branch 'master' into v2.1