Fix missing prototype for newlineScanByteCountForTesting

[Tyagiquamar]

Problem

When compiling JsonCpp with -Wmissing-prototypes (or strict compiler flags treating missing function prototypes as errors), GCC/Clang emits a compiler error in src/lib_json/json_reader.cpp:

error: no previous prototype for 'size_t& Json::newlineScanByteCountForTesting()' [-Werror=missing-prototypes]

Fixes #1705.

Solution

Add explicit prototype declaration JSON_API size_t& newlineScanByteCountForTesting(); matching the function signature before its definition in src/lib_json/json_reader.cpp.

Verification

• Built in Docker with GCC 14 and -DCMAKE_CXX_FLAGS='-Wmissing-prototypes': compiled cleanly with zero errors/warnings on newlineScanByteCountForTesting.
• Ran full test suite in Docker: all 131 tests passed (100% pass rate).

[greptile-apps]

Confidence Score: 5/5

[Low risk] Adds forward declaration for internal testing function.

The PR appears safe to merge.

Summary

The PR adds a matching forward declaration for Json::newlineScanByteCountForTesting() to address strict-compiler missing-prototype diagnostics.

• The declaration does not change parser behavior or the function’s linkage.

_{Reviews (1) · Last reviewed commit: "Fix missing prototype for newlineScanByt..."}