diff --git a/libcxxfileno/PKGBUILD b/libcxxfileno/PKGBUILD
index e7547da..ebb1c13 100644
--- a/libcxxfileno/PKGBUILD
+++ b/libcxxfileno/PKGBUILD
@@ -15,6 +15,11 @@ install=
 source=("git+https://github.com/stephenrkell/libcxxfileno")
 md5sums=('SKIP')
 
+prepare() {
+    cd "$srcdir/${_pkgname}"
+    sed -i '1ipkgincludedir=$(includedir)' include/Makefile.am
+}
+
 pkgver() {
     cd "$srcdir/${_pkgname}"
     printf "r%s.%s" "$(git rev-list --count HEAD)" "$(git rev-parse --short HEAD)"