+ Suppress extern inline (with or without __attribute__ ((__gnu_inline__)))
+ on configurations that mistakenly use 'static inline' to implement
+ functions or macros in standard C headers like <ctype.h>. For example,
+ if isdigit is mistakenly implemented via a static inline function,
+ a program containing an extern inline function that calls isdigit
+ may not work since the C standard prohibits extern inline functions
+ from calling static functions (ISO C 99 section 6.7.4.(3).
+ This bug is known to occur on:
+
+ OS X 10.8 and earlier; see:
+ https://lists.gnu.org/r/bug-gnulib/2012-12/msg00023.html
+
+ DragonFly; see
+ http://muscles.dragonflybsd.org/bulk/bleeding-edge-potential/latest-per-pkg/ah-tty-0.3.12.log
+
+ FreeBSD; see:
+ https://lists.gnu.org/r/bug-gnulib/2014-07/msg00104.html
+
+ OS X 10.9 has a macro __header_inline indicating the bug is fixed for C and
+ for clang but remains for g++; see <https://trac.macports.org/ticket/41033>.
+ Assume DragonFly and FreeBSD will be similar.
+
+ GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
+ inline semantics, unless -fgnu89-inline is used. It defines a macro
+ __GNUC_STDC_INLINE__ to indicate this situation or a macro
+ __GNUC_GNU_INLINE__ to indicate the opposite situation.
+ GCC 4.2 with -std=c99 or -std=gnu99 implements the GNU C inline
+ semantics but warns, unless -fgnu89-inline is used:
+ warning: C99 inline functions are not supported; using GNU89
+ warning: to disable this warning use -fgnu89-inline or the gnu_inline function attribute
+ It defines a macro __GNUC_GNU_INLINE__ to indicate this situation.
+ */
+#if (((defined __APPLE__ && defined __MACH__) \
+ || defined __DragonFly__ || defined __FreeBSD__) \
+ && (defined __header_inline \
+ ? (defined __cplusplus && defined __GNUC_STDC_INLINE__ \
+ && ! defined __clang__) \
+ : ((! defined _DONT_USE_CTYPE_INLINE_ \
+ && (defined __GNUC__ || defined __cplusplus)) \
+ || (defined _FORTIFY_SOURCE && 0 < _FORTIFY_SOURCE \
+ && defined __GNUC__ && ! defined __cplusplus))))
+# define _GL_EXTERN_INLINE_STDHEADER_BUG
+#endif