unix: globally add some CFLAGS on macOS

This will suppress some very chatty compiler warnings we see with LLVM 10.
Doing this globally is much simpler than handling it in every build script.

Author: indygreg

cpython-unix/build-cpython.sh

@@ -205,18 +205,14 @@ mv tmp Modules/readline-libedit.c
 
 # Most bits look at CFLAGS. But setup.py only looks at CPPFLAGS.
 # So we need to set both.
-CFLAGS="-fPIC -I${TOOLS_PATH}/deps/include -I${TOOLS_PATH}/deps/include/ncursesw"
+CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC -I${TOOLS_PATH}/deps/include -I${TOOLS_PATH}/deps/include/ncursesw"
 
 if [ "${PYBUILD_PLATFORM}" = "macos" ]; then
     CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/lib/libffi-3.2.1/include -I${TOOLS_PATH}/deps/include/uuid"
     CFLAGS="${CFLAGS} -F${MACOS_SDK_PATH}/System/Library/Frameworks"
 
     # Prevent using symbols not supported by current macOS SDK target.
     CFLAGS="${CFLAGS} -Werror=unguarded-availability-new"
-
-    # Suppress extremely frequent warnings we see in macOS SDK headers
-    # with LLVM 10.
-    CFLAGS="${CFLAGS} -Wno-nullability-completeness -Wno-expansion-to-defined"
 fi
 
 CPPFLAGS=$CFLAGS

cpython-unix/build-tcl.sh

@@ -33,10 +33,9 @@ rm -rf pkgs/sqlite* pkgs/tdbc*
 
 pushd unix
 
-CFLAGS="-fPIC -I${TOOLS_PATH}/deps/include"
+CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC -I${TOOLS_PATH}/deps/include"
 
 if [ "${PYBUILD_PLATFORM}" = "macos" ]; then
-  CFLAGS="${CFLAGS} -Wno-nullability-completeness -Wno-expansion-to-defined"
   CFLAGS="${CFLAGS} -I${MACOS_SDK_PATH}/System/Library/Frameworks -F${MACOS_SDK_PATH}/System/Library/Frameworks"
 fi
 

cpython-unix/build-tix.sh

@@ -21,10 +21,10 @@ cd cpython-source-deps-tix-${TIX_VERSION}
 # Yes, really.
 chmod +x configure
 
-CFLAGS="-fPIC -DUSE_INTERP_RESULT"
+CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC -DUSE_INTERP_RESULT"
 
 if [ "${PYBUILD_PLATFORM}" = "macos" ]; then
-    CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include -Wno-nullability-completeness -Wno-expansion-to-defined"
+    CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include"
     CFLAGS="${CFLAGS} -I${MACOS_SDK_PATH}/System/Library/Frameworks -F${MACOS_SDK_PATH}/System/Library/Frameworks"
     EXTRA_CONFIGURE_FLAGS="--without-x"
 else

cpython-unix/build-tk.sh

@@ -13,11 +13,11 @@ export PKG_CONFIG_PATH=${TOOLS_PATH}/deps/share/pkgconfig:${TOOLS_PATH}/deps/lib
 tar -xf tk${TK_VERSION}-src.tar.gz
 pushd tk${TK_VERSION}/unix
 
-CFLAGS="-fPIC"
+CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC"
 LDFLAGS=""
 
 if [ "${PYBUILD_PLATFORM}" = "macos" ]; then
-    CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include -Wno-nullability-completeness -Wno-expansion-to-defined -Wno-availability"
+    CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include -Wno-availability"
     CFLAGS="${CFLAGS} -Wno-deprecated-declarations -Wno-unknown-attributes -Wno-typedef-redefinition"
     CFLAGS="${CFLAGS} -I${MACOS_SDK_PATH}/System/Library/Frameworks -F ${MACOS_SDK_PATH}/System/Library/Frameworks"
     LDFLAGS="-L${TOOLS_PATH}/deps/lib"

cpython-unix/build.py

@@ -52,6 +52,13 @@ def add_target_env(env, platform, build_env):
         env["BUILD_TRIPLE"] = "x86_64-apple-darwin18.7.0"
         env["TARGET_TRIPLE"] = "x86_64-apple-darwin18.7.0"
         env["PATH"] = "/usr/bin:/bin"
+        env["EXTRA_TARGET_CFLAGS"] = " ".join(
+            [
+                # Suppress extremely verbose warnings we see with LLVM 10.
+                "-Wno-nullability-completeness",
+                "-Wno-expansion-to-defined",
+            ]
+        )
 
         # macOS SDK has historically been in /usr courtesy of an
         # installer provided by Xcode. But with Catalina, the files