samhain: arm build failure

| x_sh_error.c: In function 'sh_error_string':
| x_sh_error.c:1580:31: error: incompatible type for argument 1 of 'memmove'
|  #define VA_COPY(ap1, ap2)     memmove ((ap1), (ap2), sizeof (va_list))
|                                ^
| x_sh_error.c:1720:14: note: in expansion of macro 'VA_COPY'
|        /*@i@*/VA_COPY(vl2, vl);
|               ^

this patch fixes the arm build failure.

Signed-off-by: Armin Kuster <akuster808@gmail.com>

recipes-security/samhain/samhain.inc

@@ -37,6 +37,10 @@ do_unpack_extra () {
 }
 addtask unpack_extra after do_unpack before do_patch
 
+do_configure_prepend_arm() {
+    export sh_cv___va_copy=yes
+}
+
 # If we use oe_runconf in do_configure() it will by default
 # use the prefix --oldincludedir=/usr/include which is not
 # recognized by Samhain's configure script and would invariably