Move find_datadir to OS specific files.

This moves the win32 and POSIX versions of find_datadir() to OS
specific files, and removes some #ifdef clutter from vl.c

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Acked-by: Juan Quintela <quintela@redhat.com>
Acked-by: Richard Henderson <rth@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

os-win32.c

@@ -181,3 +181,26 @@ void os_setup_early_signal_handling(void)
         }
     }
 }
+
+/* Look for support files in the same directory as the executable.  */
+char *os_find_datadir(const char *argv0)
+{
+    char *p;
+    char buf[MAX_PATH];
+    DWORD len;
+
+    len = GetModuleFileName(NULL, buf, sizeof(buf) - 1);
+    if (len == 0) {
+        return NULL;
+    }
+
+    buf[len] = 0;
+    p = buf + len - 1;
+    while (p != buf && *p != '\\')
+        p--;
+    *p = 0;
+    if (access(buf, R_OK) == 0) {
+        return qemu_strdup(buf);
+    }
+    return NULL;
+}