fix missing includes (gcc15)

Author: Acly

src/visp/arch/esrgan.cpp

@@ -1,4 +1,5 @@
 #include "visp/arch/esrgan.h"
+#include "util/math.h"
 #include "util/string.h"
 #include "visp/nn.h"
 #include "visp/vision.h"

src/visp/image.cpp

@@ -8,6 +8,7 @@
 #include <stb_image_write.h>
 
 #include <algorithm>
+#include <cstring>
 #include <memory>
 #include <span>
 #include <utility>