expose capi home, if custom set

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/SysModuleBuiltins.java

@@ -195,6 +195,7 @@ public void postInitialize(PythonCore core) {
         sys.setAttribute("graal_python_home", context.getLanguage().getHome());
         sys.setAttribute("graal_python_core_home", coreHome);
         sys.setAttribute("graal_python_stdlib_home", stdlibHome);
+        sys.setAttribute("graal_python_capi_home", capiHome);
         sys.setAttribute("__flags__", core.factory().createTuple(new Object[]{
                         false, // bytes_warning
                         !PythonOptions.getFlag(context, PythonOptions.PythonOptimizeFlag), // debug

graalpython/lib-python/3/distutils/sysconfig_graalpython.py

@@ -80,7 +80,7 @@ def _init_posix():
     g['CCSHARED'] = "-fPIC"
     g['LDSHARED_LINUX'] = "%s -shared -fPIC" % sys.__graal_get_toolchain_path('CC')
     if darwin_native:
-        capi_home = sys.graal_python_core_home
+        capi_home = sys.graal_python_capi_home
         g['LDSHARED'] = g['LDSHARED_LINUX'] + " -L" + capi_home + " -lpython." + so_abi + " -Wl,-rpath," + capi_home
     else:
         g['LDSHARED'] = g['LDSHARED_LINUX']