diff --git a/configure.in b/configure.in
index e6fcbbe6..c4fc8c28 100644
--- a/configure.in
+++ b/configure.in
@@ -32,15 +32,15 @@ ARCH_LIBS=""
 ARCH_CFLAGS=""
 AC_CANONICAL_HOST
 case $host in
-	*-*-mingw32* | *-*-windows*)
+*-*-mingw32* | *-*-windows*)
 	acx_host_arch="WIN32"
 	acx_host_winapi="MSWINDOWS"
 	;;
-	*-*-darwin*)
+*-*-darwin*)
 	acx_host_arch="UNIX"
 	acx_host_winapi="CARBON"
 	;;
-	*)
+*)
 	acx_host_arch="UNIX"
 	acx_host_winapi="XWINDOWS"
 	;;
@@ -66,8 +66,15 @@ ac_ext=cpp
 dnl check compiler
 ACX_CHECK_CXX
 
-dnl macros we should do testing with
-CXXFLAGS="$CXXFLAGS -D_BSD_SOURCE -D_XOPEN_SOURCE=500"
+dnl different platforms have somewhat incompatible requirements for
+dnl BSD and Posix macros.
+case $host in
+*-*-openbsd* | *-*-freebsd*)
+	;;
+*)
+	CXXFLAGS="$CXXFLAGS -D_BSD_SOURCE -D_XOPEN_SOURCE=500"
+	;;
+esac
 
 dnl checks for libraries
 if test x"$acx_host_arch" = xUNIX; then
diff --git a/lib/arch/CArchNetworkBSD.cpp b/lib/arch/CArchNetworkBSD.cpp
index d7ecb33a..d27ab3fd 100644
--- a/lib/arch/CArchNetworkBSD.cpp
+++ b/lib/arch/CArchNetworkBSD.cpp
@@ -43,6 +43,10 @@
 #	endif
 #endif
 
+#if !HAVE_INET_ATON
+#	include <stdio.h>
+#endif
+
 #if HAVE_ALLOCA_H
 #	define freea(x_)
 #else
diff --git a/lib/common/common.h b/lib/common/common.h
index 4c0be0ae..96910efc 100644
--- a/lib/common/common.h
+++ b/lib/common/common.h
@@ -67,12 +67,6 @@
 #define __FP__
 #endif
 
-// Need this on FreeBSD to get nanosleep.  We can't define this on, say,
-// Linux because that unconditionally defines it.
-#if defined(__FreeBSD__)
-#define _POSIX_VERSION 199506L
-#endif
-
 // define NULL
 #ifndef NULL
 #define NULL 0