configure: Include #define name in check_define compiler error

Include the name of the #define being tested for in the compiler
error produced when a check_define test is run and fails. This
appears only in the config.log, but it does make it a little easier
to debug problems by inspecting config.log.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

configure

diff --git a/configure b/configure
index 5fbd812..c98aed1 100755
--- a/configure
+++ b/configure
@@ -249,7 +249,7 @@
 check_define() {
 cat > $TMPC <<EOF
 #if !defined($1)
-#error Not defined
+#error $1 not defined
 #endif
 int main(void) { return 0; }
 EOF