Added autoconf check for "inline". You can now use it, it will be
defined to (empty) for compilers that do not have it.

diff --git a/configure.in b/configure.in
index 092a4be..6371255 100644
--- a/configure.in
+++ b/configure.in
@@ -491,6 +491,7 @@
 dnl **** Check for types ****
 
 AC_C_CONST()
+AC_C_INLINE()
 AC_TYPE_SIZE_T()
 AC_CHECK_SIZEOF(long long,0)