diff --git a/CHANGES b/CHANGES
index 28c832680..76e6edf02 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,8 @@
 CHANGES SINCE FLTK 1.0.10
 
+	- Add -D_INCLUDE_POSIX_SOURCE option when compiling with
+	  the HP compilers.
+
 	- Fl_Gl_Window does not set drawbuffer(BACKBUFFER) for
 	  single-buffered windows.
 
diff --git a/configure.in b/configure.in
index 98d8ab51f..41cec00f9 100644
--- a/configure.in
+++ b/configure.in
@@ -1,7 +1,7 @@
 dnl -*- sh -*-
 dnl the "configure" script is made from this by running GNU "autoconf"
 dnl
-dnl "$Id: configure.in,v 1.33.2.23 2001/02/12 15:12:14 easysw Exp $"
+dnl "$Id: configure.in,v 1.33.2.24 2001/02/16 13:35:28 easysw Exp $"
 dnl
 dnl Configuration script for the Fast Light Tool Kit (FLTK).
 dnl
@@ -295,8 +295,8 @@ else
 		CFLAGS="+O2 $CFLAGS"
 		CXXFLAGS="+O2 +W336,501,736,740,749,829 $CXXFLAGS"
 	    fi
-	    CFLAGS="+DAportable $CFLAGS"
-	    CXXFLAGS="+DAportable $CXXFLAGS"
+	    CFLAGS="+DAportable -D_INCLUDE_POSIX_SOURCE $CFLAGS"
+	    CXXFLAGS="+DAportable -D_INCLUDE_POSIX_SOURCE $CXXFLAGS"
 	    ;;
 	SunOS*)
 	    # Solaris
@@ -332,5 +332,5 @@ AC_CONFIG_HEADER(config.h:configh.in)
 AC_OUTPUT(makeinclude)
 
 dnl
-dnl End of "$Id: configure.in,v 1.33.2.23 2001/02/12 15:12:14 easysw Exp $".
+dnl End of "$Id: configure.in,v 1.33.2.24 2001/02/16 13:35:28 easysw Exp $".
 dnl