--- dist/aclocal_java/ac_jni_include_dirs.m4	2003-10-06 20:41:38.000000000 +0200
+++ dist/aclocal_java/ac_jni_include_dirs.m4	2005-09-23 21:31:26.000000000 +0200
@@ -43,14 +43,19 @@
 *)	AC_MSG_ERROR([$_ACJNI_JAVAC is not an absolute path name]);;
 esac
 
-_ACJNI_FOLLOW_SYMLINKS("$_ACJNI_JAVAC")
-_JTOPDIR=`echo "$_ACJNI_FOLLOWED" | sed -e 's://*:/:g' -e 's:/[[^/]]*$::'`
-case "$host_os" in
-	darwin*)	_JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
-			_JINC="$_JTOPDIR/Headers";;
-	*)		_JINC="$_JTOPDIR/include";;
-esac
-
+# If JAVAPREFIX is defined, look there first
+if test -r "$JAVAPREFIX/include/jni.h"; then
+	_JTOPDIR="$JAVAPREFIX"
+	_JINC="$JAVAPREFIX/include"
+else
+	_ACJNI_FOLLOW_SYMLINKS("$_ACJNI_JAVAC")
+	_JTOPDIR=`echo "$_ACJNI_FOLLOWED" | sed -e 's://*:/:g' -e 's:/[[^/]]*$::'`
+	case "$host_os" in
+		darwin*)	_JTOPDIR=`echo "$_JTOPDIR" | sed -e 's:/[[^/]]*$::'`
+				_JINC="$_JTOPDIR/Headers";;
+		*)		_JINC="$_JTOPDIR/include";;
+	esac
+fi
 # If we find jni.h in /usr/include, then it's not a java-only tree, so
 # don't add /usr/include or subdirectories to the list of includes.
 # An extra -I/usr/include can foul things up with newer gcc's.