Add check for inline support.

config.h.in

@@ -1188,6 +1188,12 @@
 /* Define to `unsigned int' if <sys/types.h> does not define. */
 #undef id_t
 
+/* Define to `__inline__' or `__inline' if that's what the C compiler
+   calls it, or to nothing if 'inline' is not supported under any name.  */
+#ifndef __cplusplus
+#undef inline
+#endif
+
 /* Define to `unsigned int' if <sys/types.h> does not define. */
 #undef ino_t
 

configure

@@ -15931,6 +15931,48 @@ $as_echo "#define const /**/" >>confdefs.h
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for inline" >&5
+$as_echo_n "checking for inline... " >&6; }
+if ${ac_cv_c_inline+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_cv_c_inline=no
+for ac_kw in inline __inline__ __inline; do
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#ifndef __cplusplus
+typedef int foo_t;
+static $ac_kw foo_t static_foo () {return 0; }
+$ac_kw foo_t foo () {return 0; }
+#endif
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  ac_cv_c_inline=$ac_kw
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  test "$ac_cv_c_inline" != no && break
+done
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_inline" >&5
+$as_echo "$ac_cv_c_inline" >&6; }
+
+case $ac_cv_c_inline in
+  inline | yes) ;;
+  *)
+    case $ac_cv_c_inline in
+      no) ac_val=;;
+      *) ac_val=$ac_cv_c_inline;;
+    esac
+    cat >>confdefs.h <<_ACEOF
+#ifndef __cplusplus
+#define inline $ac_val
+#endif
+_ACEOF
+    ;;
+esac
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for working volatile" >&5
 $as_echo_n "checking for working volatile... " >&6; }
 if ${ac_cv_c_volatile+:} false; then :

configure.ac

@@ -2197,6 +2197,7 @@ dnl C compiler checks (to be done after os checks)
 dnl
 AC_PROG_CC_STDC
 AC_C_CONST
+AC_C_INLINE
 AC_C_VOLATILE
 AC_MSG_CHECKING([for variadic macro support in cpp])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([