Make use of GPGRT macros is available.
Make use of GPGRT macros is available.

* src/gpgme.h.in (_GPGME_INLINE): Define using GPGRT_INLINE if
possible.  Fix problem with -Wundef by adding an extra "defined()".
(_GPGME_GCC_VERSION): Define using GPGRT_ macro if possible.

gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme