packaging: fix build error by Werror

packaging: fix build error by Werror

Different semantics for inline functions

While -std=gnu89 employs the GNU89 inline semantics, -std=gnu11 uses the
C99 inline semantics. The C99 inline semantics requires that if a
function with external linkage is declared with inline function
specifier, it also has to be defined in the same translation unit (TU).
Consequently, GCC now warns if it sees a TU such as the following:

  inline int foo (void);
  This example now gives the following diagnostic:

  f.c:1:12: warning: inline function 'foo' declared but never defined
    inline int foo (void);

Change-Id: I01405d2b7820e32400d5ec193c073c7ce6e1a50a
Signed-off-by: jiyong.min <jiyong.min@samsung.com>