unix: define a more proper variable for disambiguating build target

The last one was too specific.

Author: indygreg

cpython-unix/build-openssl.sh

@@ -23,7 +23,7 @@ if [ "${CC}" = "musl-clang" ]; then
     EXTRA_FLAGS="${EXTRA_FLAGS} no-async -DOPENSSL_NO_ASYNC -D__STDC_NO_ATOMICS__=1 no-engine -DOPENSSL_NO_SECURE_MEMORY"
 fi
 
-if [ "${TARGET_TRIPLE}" = "x86_64-apple-darwin18.7.0" ]; then
+if [ "${PYBUILD_PLATFORM}" = "macos" ]; then
   OPENSSL_TARGET=darwin64-x86_64-cc
 else
   OPENSSL_TARGET=linux-x86_64

cpython-unix/build.py

@@ -45,6 +45,7 @@
 
 
 def add_target_env(env, platform, build_env):
+    env["PYBUILD_PLATFORM"] = platform
     env["NUM_CPUS"] = "%d" % multiprocessing.cpu_count()
     env["TOOLS_PATH"] = build_env.tools_path