--- a/configure.ac
+++ b/configure.ac
@@ -148,11 +148,9 @@
 
 # Is this Solaris?
 AC_MSG_CHECKING(for Solaris)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
-#if defined (__SVR4) && defined (__sun)
-	exit(0);
-#else
-	exit(-1);
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM( [], [
+#if ! ( defined (__SVR4) && defined (__sun) )
+#error "Not Solaris"
 #endif
 		])
 	],[
@@ -165,11 +163,9 @@
 
 # Is this BSDI?
 AC_MSG_CHECKING(for BSDI)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
-#if defined (__bsdi__)
-	exit(0);
-#else
-	exit(-1);
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM( [], [
+#if ! defined (__bsdi__)
+#error "Not BSDI"
 #endif
 		])
 	],[
@@ -182,11 +178,9 @@
 
 # Is this NetBSD?
 AC_MSG_CHECKING(for NetBSD)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
-#if defined (__NetBSD__)
-	exit(0);
-#else
-	exit(-1);
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM( [], [
+#if ! defined (__NetBSD__)
+#error "Not NetBSD";
 #endif
 		])
 	],[
@@ -199,11 +193,9 @@
 
 # Is this MacOS X?
 AC_MSG_CHECKING(for MacOS X)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
-#if defined (__APPLE__) && defined (__MACH__)
-	exit(0);
-#else
-	exit(-1);
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM( [], [
+#if ! ( defined (__APPLE__) && defined (__MACH__) )
+#error "Not Mac OS X"
 #endif
 		])
 	],[