diff --git a/acinclude.m4 b/acinclude.m4
index 64b465f34..181711dad 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -86,6 +86,14 @@ AC_DEFUN([GB_INIT_AUTOMAKE],
   AC_DEFINE(GAMBAS_PCODE_VERSION, 0x03050000, [Gambas bytecode version])
   AC_DEFINE(GAMBAS_PCODE_VERSION_MIN, 0x03000000, [Minimum Gambas bytecode version])
 
+  IN_REPO=$(svn info >/dev/null 2>&1 && echo yes)
+  if test -n "$IN_REPO"; then
+    ## These will go into the Makefiles. Quoting is a mess.
+    TRUNK_VERSION='$(shell svn info 2>/dev/null | grep Revision | egrep -wo "[[0-9]]+$$")'
+    AC_SUBST(TRUNK_VERSION)
+    export CPPFLAGS=$CPPFLAGS\ '-DTRUNK_VERSION=$(TRUNK_VERSION)'
+  fi
+
   GB_CLEAR_MESSAGES
 ])
 
diff --git a/main/gbx/gbx.c b/main/gbx/gbx.c
index f122da94e..e19926965 100644
--- a/main/gbx/gbx.c
+++ b/main/gbx/gbx.c
@@ -242,7 +242,13 @@ int main(int argc, char *argv[])
 		}
 		else if (is_long_option(argv[1], 'V', "version"))
 		{
+#define xstr(m)		#m
+#define stringify(m)	xstr(m)
+#ifdef TRUNK_VERSION
+			printf(VERSION " #" stringify(TRUNK_VERSION) "\n");
+#else
 			printf(VERSION "\n");
+#endif
 			my_exit(0);
 		}
 		else if (is_long_option(argv[1], 'L', "license"))