Print hashbang line in included pseudomains

Summary: Adds a function to conditionally print hashbang lines appearing in PHP files
that were included (while still not printing the hashbang line from the first
pseduomain run).

Fixes #1502

Reviewed By: @fredemmott

Differential Revision: D1664574

Signature: t1:1664574:1415307532:54c2030252ae38cffe0b06c934156403e9edd659
Use int64_t (not int) for HNI return types

Summary: PHP ints are 64-bits, so returning a 32-bit int from these functions
could plausibly leave garbage in the upper bits.

Reviewed By: @alexmalyshev

Differential Revision: D1667234

Signature: t1:1667234:1415389306:75519adb48962f2de087a84932724cea3b40b512
Use rVmSp that can be allocated to any reg.

Summary: Lower new vasm instructions for manipulating rVmSp.

Reviewed By: @edwinsmith

Differential Revision: D1666041

Signature: t1:1666041:1415359506:76118451512a34da6f85b42d476a5b52a4580840
Make LLVM emit direct calls (name-based lookup).

Summary: use named functions when creating call instructions to force
LLVM emit direct calls. Use small code model and static reloc mode.

Reviewed By: @swtaarrs

Differential Revision: D1642410
Target 3.5

Summary: 3.4 branch is cut.

Reviewed By: @JoelMarcey, @ptarjan

Differential Revision: D1664249

Signature: t1:1664249:1415307240:2d52166a259646bf00fef1d78b0e44c410047657