Merge bitcoin/bitcoin#27192: util: add missing include and fix function signature

8847ce44e0 util: add missing include and fix function signature (Cory Fields)

Pull request description:

  ping hebasto

  Discovered while testing pre-compiled header support with CMake: https://github.com/theuni/bitcoin/commits/cmake-pch-poc. Compilation of that branch fails without this fix and succeeds with it.

  Similar to the fix in #27144.

  The problem of having a default argument in the definition was masked by the missing include. Using PCH forces that include, so we end up with the compiler error we should've been getting all along.

ACKs for top commit:
  fanquake:
    ACK 8847ce44e0

Tree-SHA512: 5eb9a6691ee37cbc5033a48aedcbf5c93af3b234614ae14c3fcc858f1ee505f630ad68f8bbb69ffa280080c8d0f91451362cb3819290b741ce906b2b3224a622

src/util/readwritefile.cpp

@@ -3,6 +3,8 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <util/readwritefile.h>
+
 #include <fs.h>
 
 #include <algorithm>
@@ -11,7 +13,7 @@
 #include <string>
 #include <utility>
 
-std::pair<bool,std::string> ReadBinaryFile(const fs::path &filename, size_t maxsize=std::numeric_limits<size_t>::max())
+std::pair<bool,std::string> ReadBinaryFile(const fs::path &filename, size_t maxsize)
 {
     FILE *f = fsbridge::fopen(filename, "rb");
     if (f == nullptr)