configure: Fix wrong preprocessor statement

#abort is not a preprocessor statement. It aborts, but the preprocessor
statement #error is more common to abort a compilation.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

configure

@@ -2624,7 +2624,7 @@ int main(void) {
 #if defined(_POSIX_SYNCHRONIZED_IO) && _POSIX_SYNCHRONIZED_IO > 0
 return fdatasync(0);
 #else
-#abort Not supported
+#error Not supported
 #endif
 }
 EOF