Adds and integrates slibtool:
    - Adds ${PKG_SLIBTOOL}.
    - pkg.build: export ${MAKE} as `make LIBTOOL=${PKG_SLIBTOOL}'.
    - binutils{_host,}: use slibtool-static.
    - git: add NEEDS_SSL_WITH_CURL=1 to ${PKG_GIT_MAKEFLAGS_BUILD_EXTRA}.
    - pacman-5.0.1: add `LIBALPM_LIBS=-lssl -lbz2 -llzma -lz' to
      ${PKG_PACMAN_ENV_VARS_EXTRA}; Makefile.am patch.
    
    Introduces 32-bit (i686-nt32-midipix) support, selected by ARCH=nt32 and
    defaulting to 64-bit builds:
    - Create ${PREFIX_TARGET}/lib.
    - Remove ${PREFIX_TARGET} when cleaning the prefix if -c has been specified.
    - Set ${HOST_NATIVE}, ${TARGET}, and ${TARBALL_{SRC_,}FNAME_PREFIX} from ${ARCH}.
    - pkg.build: use ${TARGET}-dlltool instead of x86_64-nt64-midipix-dlltool.
    - glib-2.46.2: broken at present.
    - libffi-3.2.1/src/x86/win32.S: fix symbol prefix.
    - musl-1.1.12/arch/nt32/bits/syscall.h: copied from musl-1.1.12/arch/nt64/bits/syscall.h.
    - perl-5.22.1: Set --target from ${TARGET}.
    
    Bug fixes:
    - psxstub: make {_,__}so_entry_point weak symbols to express preference for
      the real psxscl shared object.
    - bash-4.3: fix lib/intl/libgnuintl.h issue.
    - libarchive-3.1.2: import FreeBSD-SA-16:23.libarchive and FreeBSD-SA-16:22.libarchive
      security fixes.
    
    Include all directories beneath ${WORKDIR} in the source tarball.
    Updated TODO list at the end of README.