configure: check ffs __builtin_ffs versionsort

Check for presence of ffs(), __builtin_ffs() and versionsort().

configure

@@ -6701,6 +6701,46 @@ fi
 
 
 
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for __builtin_ffs" >&5
+printf %s "checking for __builtin_ffs... " >&6; }
+if test ${ax_cv_have___builtin_ffs+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+
+        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+            __builtin_ffs(0)
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"
+then :
+  ax_cv_have___builtin_ffs=yes
+else $as_nop
+  ax_cv_have___builtin_ffs=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam \
+    conftest$ac_exeext conftest.$ac_ext
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ax_cv_have___builtin_ffs" >&5
+printf "%s\n" "$ax_cv_have___builtin_ffs" >&6; }
+
+    if test yes = $ax_cv_have___builtin_ffs
+then :
+
+printf "%s\n" "#define HAVE___BUILTIN_FFS 1" >>confdefs.h
+
+fi
+
 $as_echo "#define _GNU_SOURCE 1" >>confdefs.h
 
 
@@ -6726,16 +6766,25 @@ else
 fi
 done
 
-for ac_func in prlimit
-do :
-  ac_fn_c_check_func "$LINENO" "prlimit" "ac_cv_func_prlimit"
-if test "x$ac_cv_func_prlimit" = xyes; then :
-  cat >>confdefs.h <<_ACEOF
-#define HAVE_PRLIMIT 1
-_ACEOF
+ac_fn_c_check_func "$LINENO" "ffs" "ac_cv_func_ffs"
+if test "x$ac_cv_func_ffs" = xyes
+then :
+  printf "%s\n" "#define HAVE_FFS 1" >>confdefs.h
 
 fi
-done
+ac_fn_c_check_func "$LINENO" "prlimit" "ac_cv_func_prlimit"
+if test "x$ac_cv_func_prlimit" = xyes
+then :
+  printf "%s\n" "#define HAVE_PRLIMIT 1" >>confdefs.h
+
+fi
+ac_fn_c_check_func "$LINENO" "versionsort" "ac_cv_func_versionsort"
+if test "x$ac_cv_func_versionsort" = xyes
+then :
+  printf "%s\n" "#define HAVE_VERSIONSORT 1" >>confdefs.h
+
+fi
+
 
 # The Ultrix 4.2 mips builtin alloca declared by alloca.h only works
 # for constant arguments.  Useless!

configure.ac

@@ -144,6 +144,7 @@ AC_TYPE_UINT32_T
 AC_TYPE_UINT64_T
 AX_GCC_BUILTIN([__builtin_clz])
 AX_GCC_BUILTIN([__builtin_clzll])
+AX_GCC_BUILTIN([__builtin_ffs])
 
 
 AC_DEFINE([_GNU_SOURCE], 1, [Define to get access to GNU/Linux extension])
@@ -156,7 +157,7 @@ AC_CHECK_FUNCS([ftruncate gethostname getpagesize gettimeofday localtime_r \
   memchr memset mkdir mkfifo munmap nl_langinfo pselect realpath rmdir setenv \
   setlocale strcasecmp strchr strcspn strdup strerror strncasecmp strndup \
   strrchr strspn strstr strtol strtoul uname], , [AC_MSG_ERROR(bailing out)])
-AC_CHECK_FUNCS([prlimit])
+AC_CHECK_FUNCS([ffs prlimit versionsort])
 AC_FUNC_ALLOCA
 AC_FUNC_CLOSEDIR_VOID
 AC_FUNC_CHOWN

include/configure.h.in

@@ -194,6 +194,9 @@
 /* Define to 1 if you have the <fcntl.h> header file. */
 #undef HAVE_FCNTL_H
 
+/* Define to 1 if you have the `ffs' function. */
+#undef HAVE_FFS
+
 /* Define to 1 if you have the <float.h> header file. */
 #undef HAVE_FLOAT_H
 
@@ -519,6 +522,9 @@
 /* valgrind.h found */
 #undef HAVE_VALGRIND
 
+/* Define to 1 if you have the `versionsort' function. */
+#undef HAVE_VERSIONSORT
+
 /* Define to 1 if you have the `vfork' function. */
 #undef HAVE_VFORK
 
@@ -543,6 +549,9 @@
 /* Define to 1 if the system has the `__builtin_clzll' built-in function */
 #undef HAVE___BUILTIN_CLZLL
 
+/* Define to 1 if the system has the `__builtin_ffs' built-in function */
+#undef HAVE___BUILTIN_FFS
+
 /* Define to 1 to include built-in support for integrity. */
 #undef INTEGRITY_INTERNAL