f2fs utils: set correct dependency on dynamic libf2fs

Don't link against it anymore.
Just let dlopen() deal with it correctly.
The "config" struct will come from the f2fs_ioutils
and libf2fs_fmt_host expects to have it global, so let
link with -rdynamic and let dlopen() resolve it.

Be more aggressive with linux-only builds.

Bug: 15717498
Change-Id: I03ebebed1fc652170b44f809df42c1f8595216eb
Signed-off-by: JP Abgrall <jpa@google.com>
diff --git a/f2fs_utils/f2fs_dlutils.c b/f2fs_utils/f2fs_dlutils.c
index 6fddc6e..40be416 100644
--- a/f2fs_utils/f2fs_dlutils.c
+++ b/f2fs_utils/f2fs_dlutils.c
@@ -52,7 +52,7 @@
 int dlopenf2fs() {
 	void* f2fs_lib;
 
-	f2fs_lib = dlopen(F2FS_DYN_LIB, RTLD_LAZY);
+	f2fs_lib = dlopen(F2FS_DYN_LIB, RTLD_NOW);
 	if (!f2fs_lib) {
 		return -1;
 	}