1 files changed, 69 insertions, 0 deletions
diff --git a/m4/fp_find_libffi.m4 b/m4/fp_find_libffi.m4
new file mode 100644
index 0000000000..ddc511553c
--- /dev/null
+++ b/m4/fp_find_libffi.m4
@@ -0,0 +1,69 @@
+dnl ** Have libffi?
+dnl --------------------------------------------------------------
+dnl Sets UseSystemLibFFI.
+AC_DEFUN([FP_FIND_LIBFFI],
+[
+  # system libffi
+
+  AC_ARG_WITH([system-libffi],
+  [AS_HELP_STRING([--with-system-libffi],
+    [Use system provided libffi for RTS [default=no]])
+  ])
+
+  AS_IF([test "x$with_system_libffi" = "xyes"],
+    [UseSystemLibFFI="YES"],
+    [UseSystemLibFFI="NO"]
+  )
+
+  AC_ARG_WITH([ffi-includes],
+  [AS_HELP_STRING([--with-ffi-includes=ARG],
+    [Find includes for libffi in ARG [default=system default]])
+  ],
+  [
+   if test "x$UseSystemLibFFI" != "xYES"; then
+      AC_MSG_WARN([--with-ffi-includes will be ignored, --with-system-libffi not set])
+   else
+      FFIIncludeDir="$withval"
+      LIBFFI_CFLAGS="-I$withval"
+   fi
+  ])
+
+  AC_SUBST(FFIIncludeDir)
+
+  AC_ARG_WITH([ffi-libraries],
+  [AS_HELP_STRING([--with-ffi-libraries=ARG],
+    [Find libffi in ARG [default=system default]])
+  ],
+  [
+   if test "x$UseSystemLibFFI" != "xYES"; then
+      AC_MSG_WARN([--with-ffi-libraries will be ignored, --with-system-libffi not set])
+   else
+      FFILibDir="$withval" LIBFFI_LDFLAGS="-L$withval"
+   fi
+  ])
+
+  AC_SUBST(FFILibDir)
+
+  AS_IF([test "$UseSystemLibFFI" = "YES"], [
+   CFLAGS2="$CFLAGS"
+   CFLAGS="$LIBFFI_CFLAGS $CFLAGS"
+   LDFLAGS2="$LDFLAGS"
+   LDFLAGS="$LIBFFI_LDFLAGS $LDFLAGS"
+   if test "$HostOS" = "openbsd";
+   then
+     # OpenBSD's libffi is not directly linked to the libpthread but
+     # still requires pthread functionality. This means that any client
+     # binary which links with libffi also needs to link with
+     # libpthread. If it does not, then linking fails with unresolved
+     # symbols.
+     LDFLAGS="$LDFLAGS -lpthread"
+   fi
+   AC_CHECK_LIB(ffi, ffi_call,
+    [AC_CHECK_HEADERS([ffi.h], [break], [])
+     AC_DEFINE([HAVE_SYSTEM_LIBFFI], [1], [Define to 1 if you have libffi.])],
+    [AC_MSG_ERROR([Cannot find system libffi])])
+   CFLAGS="$CFLAGS2"
+   LDFLAGS="$LDFLAGS2"
+  ])
+])
+