ARROW-8346: [CI][GLib] Follow pkg-config change in Homebrew

pkg-config in Homebrew stopped adding a pkg-config path to find system
zlib. We need to add the path manually.

See Homebrew/brew#5068 for details.

Closes #6857 from kou/ci-glib-macos

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

ci/scripts/c_glib_build.sh

@@ -26,6 +26,12 @@ build_dir=${2}/c_glib
 
 export PKG_CONFIG_PATH=${ARROW_HOME}/lib/pkgconfig
 
+if which brew > /dev/null 2>&1; then
+  export $(echo env | brew sh | grep "^HOMEBREW_SDKROOT=")
+  export $(echo env | brew sh | grep "^PKG_CONFIG=")
+  PKG_CONFIG_PATH=${PKG_CONFIG_PATH}:$(echo 'echo $PKG_CONFIG_LIBDIR' | brew sh)
+fi
+
 export CFLAGS="-DARROW_NO_DEPRECATED_API"
 export CXXFLAGS="-DARROW_NO_DEPRECATED_API"