[3.10] Update GitHub CI workflow for macOS. (GH-105304)

Author: ned-deily

.github/workflows/build.yml

@@ -184,9 +184,8 @@ jobs:
       run: brew install pkg-config openssl@1.1 xz gdbm tcl-tk
     - name: Configure CPython
       run: |
-        CFLAGS="-I$(brew --prefix gdbm)/include -I$(brew --prefix xz)/include" \
-        LDFLAGS="-L$(brew --prefix gdbm)/lib -I$(brew --prefix xz)/lib" \
-        PKG_CONFIG_PATH="$(brew --prefix tcl-tk)/lib/pkgconfig" \
+        CPPFLAGS="-I$(brew --prefix gdbm)/include -I$(brew --prefix xz)/include" \
+        LDFLAGS="-L$(brew --prefix gdbm)/lib -L$(brew --prefix xz)/lib" \
         ./configure \
           --with-pydebug \
           --prefix=/opt/python-dev \