Work around -Werror,-Wkeyword-macro

...where liblangtag/lt-macros.h does #undef inline because LT_HAVE_INLINE is not
defined---liblangtag has a config.h (that would define it), but for whatever
reason does not include it...

Change-Id: I6a6f0a3522b7aef12573af7d7c4c00bb0f1368eb