diff --git a/META.bigstring.template b/META.bigstring.template
deleted file mode 100644
index fc6c18c..0000000
--- a/META.bigstring.template
+++ /dev/null
@@ -1 +0,0 @@
-xen_linkopts = "-lbigstringaf_stubs_xen"
diff --git a/META.bigstringaf.template b/META.bigstringaf.template
new file mode 100644
index 0000000..ab74057
--- /dev/null
+++ b/META.bigstringaf.template
@@ -0,0 +1,4 @@
+# JBUILDER_GEN
+
+xen_linkopts = "-l:xen/libbigstringaf_xen_stubs.a"
+freestanding_linkopts = "-l:freestanding/libbigstringaf_freestanding_stubs.a"
diff --git a/lib/freestanding/cflags.sh b/lib/freestanding/cflags.sh
new file mode 100755
index 0000000..276e29e
--- /dev/null
+++ b/lib/freestanding/cflags.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+export PKG_CONFIG_PATH="$(opam config var lib)/pkgconfig"
+flags="$(pkg-config --static ocaml-freestanding --cflags)"
+echo "($flags)"
diff --git a/lib/freestanding/jbuild b/lib/freestanding/jbuild
new file mode 100644
index 0000000..1d9b3b4
--- /dev/null
+++ b/lib/freestanding/jbuild
@@ -0,0 +1,18 @@
+(jbuild_version 1)
+
+(library
+ ((name        bigstringaf_freestanding)
+  (public_name bigstringaf.freestanding)
+  (optional)
+  (libraries   (bigarray mirage-solo5))
+  (c_names     (bigstringaf_stubs))
+  (c_flags     (:include cflags.sexp))))
+
+(rule (copy# ../bigstringaf_stubs.c bigstringaf_stubs.c))
+(rule (copy# ../bigstringaf.ml bigstringaf.ml))
+(rule (copy# ../bigstringaf.mli bigstringaf.mli))
+
+(rule
+ ((targets (cflags.sexp))
+  (deps    (cflags.sh))
+  (action  (bash "./${<} > ${@}"))))
diff --git a/lib/jbuild b/lib/jbuild
index 909d5b1..3e3d0d9 100644
--- a/lib/jbuild
+++ b/lib/jbuild
@@ -11,13 +11,3 @@
     (javascript_files (runtime.js))
     ))
   ))
-
-(rule (copy# bigstringaf_stubs.c bigstringaf_stubs_xen.c))
-
-(rule
- (with-stdout-to cflags-xen.sexp
-  (progn
-   (echo "(")
-   (run pkg-config pkg-config --static mirage-xen --cflags)
-   (echo ")")
-   )))
diff --git a/lib/xen/cflags.sh b/lib/xen/cflags.sh
new file mode 100755
index 0000000..9a246e1
--- /dev/null
+++ b/lib/xen/cflags.sh
@@ -0,0 +1,4 @@
+#!/bin/sh
+export PKG_CONFIG_PATH="$(opam config var lib)/pkgconfig"
+flags="$(pkg-config --static mirage-xen-posix --cflags)"
+echo "($flags)"
diff --git a/lib/xen/jbuild b/lib/xen/jbuild
new file mode 100644
index 0000000..5676dde
--- /dev/null
+++ b/lib/xen/jbuild
@@ -0,0 +1,18 @@
+(jbuild_version 1)
+
+(library
+ ((name        bigstringaf_xen)
+  (public_name bigstringaf.xen)
+  (optional)
+  (libraries   (bigarray mirage-xen))
+  (c_names     (bigstringaf_stubs))
+  (c_flags     (:include cflags.sexp))))
+
+(rule (copy# ../bigstringaf_stubs.c bigstringaf_stubs.c))
+(rule (copy# ../bigstringaf.ml bigstringaf.ml))
+(rule (copy# ../bigstringaf.mli bigstringaf.mli))
+
+(rule
+ ((targets (cflags.sexp))
+  (deps    (cflags.sh))
+  (action  (bash "./${<} > ${@}"))))