Update to 1.4.1

Changelog:
Changes from 1.4.0 to 1.4.1:
----------------------------

* Bug fixes:
  - revert some quoting changes because they don't work well with certain
    GCC edge cases (#168)

* Enhancements:
  - add limited support for --cflags with --msvc-syntax

Changes from 1.3.7 to 1.4.0:
----------------------------

* Notable libpkgconf API changes:
  - pkgconf_pkg_t.requires has been renamed to pkgconf_pkg_t.required for
    C++20 compatibility.

* Enhancements:
  - pkgconf and libpkgconf has been ported to Windows as native binaries.
  - improved compatibility with freedesktop.org pkg-config's ${pc_sysrootdir}
    usage pattern.
  - do not mention PKG_CONFIG_SKIP_CONFLICTS environmental variable when
    simplified errors are requested, as with PKG_CONFIG_PATH.
  - the dependency solver now stores solutions to dependency graph elements
    it visits, allowing for the dependency graph to be incrementally solved.
    this improves dependency solving time by an order of magnitude in most
    cases.
  - new --env option allows for exporting cflags/libs fragments as export
    variables
  - new support for building pkgconf with CMake and Meson
  - improved compiler warning flag detection on autoconf and CMake
  - removed PKGCONF_BUFSIZE allocations from the stack where possible
  - allow for customizing the way fragment lists are rendered using
    a callback API
  - new support for --msvc-syntax output using the new fragment rendering
    callbacks
  - fragments are now quoted according to POSIX literal rules
  - new variables on the pkg-config builtin:
    - ${pc_system_includedirs}: the system includedir search path known
      by pkgconf
    - ${pc_system_libdirs}: the system libdir search path known by pkgconf
  - new manpages:
    - pc(5) describing pkgconf's interpretation of pkg-config .pc files
    - pkg.m4(7) describing the autotools macros bundled with pkgconf

* Bug fixes:
  - fix pkgconf_pkg_t.id generation on native Windows where either \ or /
    are usable as path separator.
  - add missing --modversion to --help output
  - do not evaluate module paths for modules that are not actually on disk
  - ensure we work on a zeroed buffer prior to calling realpath(2) with it
  - fix path deduplication edge case when cache-inodes feature is unavailable
  - fix path rewriting regression with PKG_CONFIG_SYSROOT_DIR when
    PKG_CONFIG_SYSROOT_DIR is set to /
  - fix crash in edge case where a .pc file has misquoting in a fragment list.
  - fix logic edge case when comparing relocated paths

Changes from 1.3.6 to 1.3.7:
----------------------------

* Enhancements:
  - improved diagnostics for malformed packages.

* Bug fixes:
  - reject packages which contain incomplete metadata in post-parse phase.

Changes from 1.3.5 to 1.3.6:
----------------------------

* Enhancements:
  - add many cflags to the protected set: -Wa, -Wl, -Wp, -ansi, -std=, -stdlib=,
    -pedantic, -pthread, -trigraphs, -nostdinc, -nostdlibinc, -nobuiltininc.

* Bug fixes:
- handle -include cflag fragments properly.


(ryoon)