unix: ensure some warnings are not errors

Clang 16 makes `implicit-function-declarations` and
`incompatible-function-pointer-types` errors by default instead of
warnings. This commit adds the compiler flag to ensure they remain
warnings and not errors.

cpython-unix/build-tix.sh

@@ -23,6 +23,11 @@ chmod +x configure
 
 CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC -DUSE_INTERP_RESULT"
 
+# Error by default in Clang 16.
+if [ "${CC}" = "clang" ]; then
+    CFLAGS="${CFLAGS} -Wno-error=implicit-function-declaration -Wno-error=incompatible-function-pointer-types"
+fi
+
 if [ "${PYBUILD_PLATFORM}" = "macos" ]; then
     CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include"
     EXTRA_CONFIGURE_FLAGS="--without-x"

cpython-unix/build-uuid.sh

@@ -12,7 +12,12 @@ export PATH=${TOOLS_PATH}/${TOOLCHAIN}/bin:${TOOLS_PATH}/host/bin:$PATH
 tar -xf libuuid-${UUID_VERSION}.tar.gz
 pushd libuuid-${UUID_VERSION}
 
-CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC" CPPFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC" LDFLAGS="${EXTRA_TARGET_LDFLAGS}" ./configure \
+CFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC"
+
+# Error by default in Clang 16.
+CFLAGS="${CFLAGS} -Wno-error=implicit-function-declaration"
+
+CFLAGS="${CFLAGS}" CPPFLAGS="${EXTRA_TARGET_CFLAGS} -fPIC" LDFLAGS="${EXTRA_TARGET_LDFLAGS}" ./configure \
     --build=${BUILD_TRIPLE} \
     --host=${TARGET_TRIPLE} \
     --prefix=/tools/deps \