move to using C headers in minimal_benchmark.h to prevent getting any C++ STL headers
diff --git a/include/benchmark/minimal_benchmark.h b/include/benchmark/minimal_benchmark.h
index 60038e0..c9ffee1 100644
--- a/include/benchmark/minimal_benchmark.h
+++ b/include/benchmark/minimal_benchmark.h
@@ -135,9 +135,9 @@
 #ifndef BENCHMARK_MINIMAL_BENCHMARK_H_
 #define BENCHMARK_MINIMAL_BENCHMARK_H_
 
-#include <cassert>
-#include <cstddef>
-#include <cstdint>
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
 
 #include "macros.h"