The inline keyword is not part of ANSI C and the library does not
export any inline function definitions by default. However, the library
provides optional inline versions of performance-critical functions by
conditional compilation.  The inline versions of these functions can be
included by defining the macro HAVE_INLINE when compiling an
application.
gcc -c -DHAVE_INLINE app.c
If you use autoconf this macro can be defined automatically.
The following test should be placed in your `configure.in' file,
AC_C_INLINE if test "$ac_cv_c_inline" != no ; then AC_DEFINE(HAVE_INLINE,1) AC_SUBST(HAVE_INLINE) fi
and the macro will then be defined in the compilation flags or by
including the file `config.h' before any library headers.  If you
do not define the macro HAVE_INLINE then the slower non-inlined
versions of the functions will be used instead.
Note that the actual usage of the inline keyword is extern
inline, which eliminates unnecessary function definitions in GCC.
If the form extern inline causes problems with other compilers a
stricter autoconf test can be used, see section Autoconf Macros.