Use a Makefile to build libmirage-xen_bindings.a

The C code in bindings/ *must* be built using exact C flags and linked
only statically. Until there is a way to do this in an OCaml + dune +
Mirage environment, we need to use Makefile here.

dune-project

@@ -1,2 +1,2 @@
-(lang dune 2.0)
+(lang dune 2.6)
 (name mirage-xen)

lib/bindings/Makefile

@@ -0,0 +1,18 @@
+PKG_CONFIG_PATH := $(shell opam config var prefix)/lib/pkgconfig
+
+CC ?= cc
+FREESTANDING_CFLAGS := $(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --cflags ocaml-freestanding)
+CFLAGS := $(FREESTANDING_CFLAGS) \
+    -O2 -std=c99 -Wall -Werror \
+    -Iinclude -D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__
+
+.PHONY: all clean
+all: libmirage-xen_bindings.a
+
+OBJS=alloc_pages_stubs.o atomic_stubs.o barrier_stubs.o bmap.o checksum_stubs.o clock_stubs.o cstruct_stubs.o evtchn.o gnttab.o main.o mm_stubs.o
+
+libmirage-xen_bindings.a: $(OBJS)
+	$(AR) r $@ $^
+
+clean:
+	$(RM) $(OBJS) libmirage-xen_bindings.a

lib/dune

@@ -2,23 +2,22 @@
  (name oS)
  (public_name mirage-xen)
  (libraries lwt cstruct xenstore.client shared-memory-ring-lwt
-            mirage-profile logs io-page fmt mirage-runtime)
- (foreign_archives mirage-xen_bindings))
+            mirage-profile logs io-page fmt mirage-runtime))
 
-(foreign_library
- (archive_name mirage-xen_bindings)
- (language c)
- (include_dirs ../include)
- (names main bmap evtchn gnttab
-        alloc_pages_stubs atomic_stubs barrier_stubs checksum_stubs clock_stubs
-        cstruct_stubs mm_stubs)
- (flags (:include cflags.sexp) -O2 -std=c99 -Wall -Werror
-        -D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__))
+(rule
+ (deps (source_tree bindings))
+ (targets libmirage-xen_bindings.a)
+ (action
+ (no-infer
+  (progn
+   (chdir bindings (run make))
+   (copy bindings/libmirage-xen_bindings.a libmirage-xen_bindings.a)))))
 
 (include_subdirs unqualified)
 
 (rule (with-stdout-to cflags.sexp (run ./cflags.sh)))
 
 (install
  (section lib)
- (files (bindings/mirage-xen.pc as ../pkgconfig/mirage-xen.pc)))
+ (files (bindings/mirage-xen.pc as ../pkgconfig/mirage-xen.pc)
+   (libmirage-xen_bindings.a as libmirage-xen_bindings.a)))