Fix typo in doc
Various compatibility fixes and improvements to msvcc.sh.

* Don't try to mix incompatible optimization flags in debug builds.
* Workaround ax_cc_maxopt.m4 not supporting MSVC and change -O3 to -O2.
* Fix MSVC warning by properly passing linker flags to compiler.
* Make msvcc.sh return 1 if invalid command line options are used rather than silently eating them.
* Add more comments.
Merge pull request #107 from rvandermeulen/msvcc

Various compatibility fixes and improvements to msvcc.sh.
win32.S: Make calls to ffi_closure_SYSV_inner position-independent

Now that non-Windows platforms include win32.S, it needs to support
building as position-independent code.  This fixes one source of build
failures on target platforms that do not allow text relocations.
win32.S: Make the jump tables position-independent

Now that non-Windows platforms include win32.S, it needs to support
building as position-independent code.  This fixes build failures on
target platforms that do not allow text relocations.
win32.S: Use shifting for multiplication rather than repeated addition

The jump table code added a register to itself twice to multiply by 4;
shift the register left by 2 instead.
win32.S: Add handling for position-independent code on Darwin

Newer versions of Darwin generate the necessary stub functions
automatically and just need a call instruction, but accomodating older
versions as well requires adding the stub.
Avoid referencing undefined ABIs on 64-bit Windows builds

64-bit Windows does not have FFI_STDCALL, FFI_THISCALL, or FFI_FASTCALL.
Fix a warning on 64-bit Windows

When sizeof(size_t) != sizeof(unsigned), adding a size_t to cif->bytes
produces a "possible loss of data" warning.  However, the size_t in
question refers to the size of a single parameter.  Use a cast to avoid
the warning.
Always use configure to detect whether global symbols need underscores

64-bit Windows already used this check; make it universal, and use it in
place of an ifdef on X86_WIN32, to handle non-Windows platforms that use
the underscore, such as Darwin.
Compile win32.S on 32-bit Darwin as well
Compile win32.S on FreeBSD
Merge pull request #105 from joshtriplett/win32-relocations

[3.1 blocker] win32.S needs to handle relocations/GOT
Merge pull request #110 from joshtriplett/w64

Fix 64-bit Windows support
Merge pull request #106 from joshtriplett/darwin-award

[3.1 blocker] Update OS X build system to include win32.S on 32-bit
Merge pull request #108 from joshtriplett/freebsd

[3.1 blocker] Fix FreeBSD support
Update copyright date and clean up README notes.
Upgrade version to 3.1-rc1
Stop setting an empty AM_RUNTESTFLAGS
Stop looking for expect and runtest above top_builddir

Users wishing to test hand-compiled versions of expect and runtest can
easily enough put them in their path or set EXPECT and RUNTEST
themselves.