build_environment.py: expand SPACK_MANAGED_DIRS with realpath (#43844)

lib/spack/env/cc

@@ -174,18 +174,6 @@ preextend() {
     unset IFS
 }
 
-# eval this because SPACK_MANAGED_DIRS and SPACK_SYSTEM_DIRS are inputs we don't wanna loop over.
-# moving the eval inside the function would eval it every call.
-eval "\
-path_order() {
-case \"\$1\" in
-    $SPACK_MANAGED_DIRS) return 0 ;;
-    $SPACK_SYSTEM_DIRS) return 2 ;;
-    /*) return 1 ;;
-esac
-}
-"
-
 # Fail with a clear message if the input contains any bell characters.
 if eval "[ \"\${*#*${lsep}}\" != \"\$*\" ]"; then
     die "Compiler command line contains our separator ('${lsep}'). Cannot parse."
@@ -198,6 +186,18 @@ for param in $params; do
     fi
 done
 
+# eval this because SPACK_MANAGED_DIRS and SPACK_SYSTEM_DIRS are inputs we don't wanna loop over.
+# moving the eval inside the function would eval it every call.
+eval "\
+path_order() {
+case \"\$1\" in
+    $SPACK_MANAGED_DIRS) return 0 ;;
+    $SPACK_SYSTEM_DIRS) return 2 ;;
+    /*) return 1 ;;
+esac
+}
+"
+
 # Check if optional parameters are defined
 # If we aren't asking for debug flags, don't add them
 if [ -z "${SPACK_ADD_DEBUG_FLAGS:-}" ]; then