Fix Xen support

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 ")")
-   )))

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)"

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 "./${<} > ${@}"))))