diff --git a/pyodide_build/cli/build_recipes.py b/pyodide_build/cli/build_recipes.py
index e930b441..8c780fb7 100644
--- a/pyodide_build/cli/build_recipes.py
+++ b/pyodide_build/cli/build_recipes.py
@@ -71,22 +71,16 @@ def build_recipes_no_deps(
         help="The directory where build directories for packages are created. "
         "Default: recipe_dir.",
     ),
-    cflags: str = typer.Option(
-        "", help="Extra compiling flags. Default: SIDE_MODULE_CFLAGS"
-    ),
-    cxxflags: str = typer.Option(
-        "", help="Extra compiling flags. Default: SIDE_MODULE_CXXFLAGS"
-    ),
-    ldflags: str = typer.Option(
-        "", help="Extra linking flags. Default: SIDE_MODULE_LDFLAGS"
-    ),
+    cflags: str = typer.Option("", help="Extra compiling flags."),
+    cxxflags: str = typer.Option("", help="Extra compiling flags."),
+    ldflags: str = typer.Option("", help="Extra linking flags."),
     target_install_dir: str = typer.Option(
         "",
-        help="The path to the target Python installation. Default: TARGETINSTALLDIR",
+        help="The path to the target Python installation.",
     ),
     host_install_dir: str = typer.Option(
         "",
-        help="Directory for installing built host packages. Default: HOSTINSTALLDIR",
+        help="Directory for installing built host packages.",
     ),
     force_rebuild: bool = typer.Option(
         False,
@@ -188,22 +182,16 @@ def build_recipes(
     no_deps: bool = typer.Option(
         False, help="Removed, use `pyodide build-recipes-no-deps` instead."
     ),
-    cflags: str = typer.Option(
-        None, help="Extra compiling flags. Default: SIDE_MODULE_CFLAGS"
-    ),
-    cxxflags: str = typer.Option(
-        None, help="Extra compiling flags. Default: SIDE_MODULE_CXXFLAGS"
-    ),
-    ldflags: str = typer.Option(
-        None, help="Extra linking flags. Default: SIDE_MODULE_LDFLAGS"
-    ),
+    cflags: str = typer.Option(None, help="Extra compiling flags."),
+    cxxflags: str = typer.Option(None, help="Extra compiling flags."),
+    ldflags: str = typer.Option(None, help="Extra linking flags."),
     target_install_dir: str = typer.Option(
         "",
-        help="The path to the target Python installation. Default: TARGETINSTALLDIR",
+        help="The path to the target Python installation.",
     ),
     host_install_dir: str = typer.Option(
         "",
-        help="Directory for installing built host packages. Default: HOSTINSTALLDIR",
+        help="Directory for installing built host packages.",
     ),
     log_dir: str = typer.Option(None, help="Directory to place log files"),
     force_rebuild: bool = typer.Option(
diff --git a/pyodide_build/config.py b/pyodide_build/config.py
index 0c519760..fd3d7eda 100644
--- a/pyodide_build/config.py
+++ b/pyodide_build/config.py
@@ -256,7 +256,7 @@ def _get_make_environment_vars(self) -> Mapping[str, str]:
 DEFAULT_CONFIG_COMPUTED: dict[str, str] = {
     # Compiler flags
     "cflags": "$(CFLAGS_BASE) -I$(PYTHONINCLUDE)",
-    "cxxflags": "$(CXXFLAGS_BASE)",
+    "cxxflags": "$(CFLAGS_BASE)",
     "ldflags": "$(LDFLAGS_BASE) -s SIDE_MODULE=1",
     # Rust-specific configuration
     "pyo3_cross_lib_dir": "$(CPYTHONINSTALL)/sysconfigdata",  # FIXME: pyodide xbuildenv stores sysconfigdata here