Trac #32207: homebrew llvm / clang - followup to #30835

in #30835 problems with using clang(++) from Homebrew on macOS were
found

* Pillow build broken
* PATH needs to be adjusted (?)

After Pillow update to 9.0.1 the only problem is caused by an obsolete
workaround
for Darwin/XCode in Pillow's spkg-install. The branch here removes it.

URL: https://trac.sagemath.org/32207
Reported by: dimpase
Ticket author(s): Dima Pasechnik
Reviewer(s): John Palmieri

build/pkgs/pillow/spkg-install.in

@@ -6,13 +6,6 @@ rm -rf \
    "$SAGE_LOCAL"/lib/python*/site-packages/PIL-*.egg* \
    "$SAGE_LOCAL"/lib/python*/site-packages/Pillow-*.egg*
 
-if [ "$UNAME" = "Darwin" ] ; then
-    # #29019
-    # https://github.com/python-pillow/Pillow/issues/3438#issuecomment-555019284
-    # https://apple.stackexchange.com/questions/372032/usr-include-missing-on-macos-catalina-with-xcode-11/372600#372600
-    export CPATH="$CPATH:`xcrun --show-sdk-path`/usr/include"
-fi
-
 if [ "$CONDA_PREFIX" != "" ]; then
     # Quoted quotes so that whitespace in CONDA_PREFIX works correctly.
     # Below we run the command line through eval.