hip-gen: add explicit #include <cstring> for chipStar compatibility

chipStar HIP headers do not transitively include <cstring>, causing
build failures for the four pre-existing strcmp() calls in this file
(resource_root comparisons). AMD ROCm headers include it transitively,
so this is a no-op on non-chipStar builds.

Author: pvelesko

backends/hip-gen/ceed-hip-gen-operator-build.cpp

@@ -12,6 +12,7 @@
 #include <ceed/gen-tools.h>
 #include <ceed/jit-tools.h>
 
+#include <cstring>
 #include <iostream>
 #include <sstream>
 #include <string>