diff --git a/sys-libs/libcxxabi/libcxxabi-15.0.0.9999.ebuild b/sys-libs/libcxxabi/libcxxabi-15.0.0.9999.ebuild
index d16cb515b1e61..6ea01b5466e1a 100644
--- a/sys-libs/libcxxabi/libcxxabi-15.0.0.9999.ebuild
+++ b/sys-libs/libcxxabi/libcxxabi-15.0.0.9999.ebuild
@@ -5,7 +5,8 @@ EAPI=8
 
 CMAKE_ECLASS=cmake
 PYTHON_COMPAT=( python3_{8..10} )
-inherit cmake-multilib llvm llvm.org python-any-r1 toolchain-funcs
+inherit cmake-multilib flag-o-matic llvm llvm.org python-any-r1 \
+	toolchain-funcs
 
 DESCRIPTION="Low level support for a standard C++ library"
 HOMEPAGE="https://libcxxabi.llvm.org/"