macOS 11 arm64 homebrew configure file tweaks

[hrbrmstr]

as per the twitter thread, I ended up having to tweak PKG_CONFIG_NAME, PKG_BREW_NAME, and PKG_LIBS:

# Library settings
PKG_CONFIG_NAME="freetype2 libpng libtiff-4 webp harfbuzz"
PKG_DEB_NAME="libfreetype6-dev libpng-dev libtiff5-dev libjpeg-dev"
PKG_RPM_NAME="freetype-devel libpng-devel libtiff-devel libjpeg-turbo-devel"
PKG_CSW_NAME="libfreetype_dev libpng16_dev libtiff_dev libjpeg_dev"
PKG_BREW_NAME="freetype libpng libtiff zlib libjpeg-turbo webp harfbuzz"
PKG_TEST_HEADER="#include <ft2build.h>\n#include <png.h>\n#include <tiffio.h>\n#include <jpeglib.h>\n"
PKG_LIBS="-lfreetype -lpng16 -ltiff -lz -ljpeg -lbz2 -lwebp -lharfbuzz"
PKG_CFLAGS=""

as well as:

  PKG_CFLAGS=``/opt/homebrew/bin/pkg-config --cflags ${PKG_CONFIG_NAME}`
  PKG_LIBS=``/opt/homebrew/bin/pkg-config --libs ${PKG_CONFIG_NAME}`
  PKG_LIBS="$PKG_LIBS -ljpeg -lwebp"

to get it to compile.

Compilation also requires a full Xcode installation.