diff --git a/configure.in b/configure.in
index 4ab2446e73..aeb8ddf6fb 100644
--- a/configure.in
+++ b/configure.in
@@ -1,7 +1,7 @@
 dnl Process this file with autoconf to produce a configure script.
 AC_INIT()
 
-AC_PREREQ(2.58)
+AC_PREREQ(2.60)
 
 AC_ARG_WITH(baseruby,
 	[  --with-baseruby=RUBY use RUBY as baseruby; RUBY is the pathname of ruby],
@@ -243,8 +243,7 @@ AC_PROG_MAKE_SET
 AC_PROG_INSTALL
 
 # checks for UNIX variants that set C preprocessor variables
-AC_AIX
-AC_MINIX
+AC_USE_SYSTEM_EXTENSIONS
 
 AC_SUBST(RM, ['rm -f'])
 AC_SUBST(CP, ['cp'])
@@ -1624,7 +1623,6 @@ fi
 MINIDLNOBJ=dln.o
 case "$target_os" in
     linux*)
-	XCFLAGS="$XCFLAGS -D_GNU_SOURCE=1"
 	;;
     netbsd*)
     	CFLAGS="$CFLAGS -pipe"