diff --git a/ChangeLog b/ChangeLog
index 93c1fd7b..432b1fe1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2001-04-06  Hrvoje Niksic  <hniksic@arsdigita.com>
+
+	* aclocal.m4 (AM_PROG_CC_STDC): Don't use -Xc under SYSV.  It
+	forces strict ANSI mode, which means we lose `long long'.
+	Generally, don't require __STDC__ to be defined to 1 because that
+	signifies strict ANSI.
+
 2001-04-04  Hrvoje Niksic  <hniksic@arsdigita.com>
 
 	* NEWS: Cosmetic changes.
diff --git a/aclocal.m4 b/aclocal.m4
index e1a1fcb7..decbba7a 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -47,12 +47,11 @@ ac_save_CC="$CC"
 # AIX			-qlanglvl=ansi
 # Ultrix and OSF/1	-std1
 # HP-UX			-Aa -D_HPUX_SOURCE
-# SVR4			-Xc -D__EXTENSIONS__
-for ac_arg in "" -qlanglvl=ansi -std1 "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+for ac_arg in "" -qlanglvl=ansi -std1 "-Aa -D_HPUX_SOURCE"
 do
   CC="$ac_save_CC $ac_arg"
   AC_TRY_COMPILE(
-[#if !defined(__STDC__) || __STDC__ != 1
+[#if !defined(__STDC__)
 choke me
 #endif
 /* DYNIX/ptx V4.1.3 can't compile sys/stat.h with -Xc -D__EXTENSIONS__. */