cmake: SILKWORM_ALLOW_UNUSED_VAR_WARNINGS build option (#2052)

Author: battlmonstr

CMakeLists.txt

@@ -55,6 +55,7 @@ option(SILKWORM_CLANG_TIDY "Clang-Tidy linter" OFF)
 option(SILKWORM_SANITIZE "Build instrumentation for sanitizers" OFF)
 option(SILKWORM_FUZZER "Build instrumentation for fuzzers" OFF)
 option(SILKWORM_USE_MIMALLOC "Enable using mimalloc for dynamic memory management" ON)
+option(SILKWORM_ALLOW_UNUSED_VAR_WARNINGS "Turn unused variable errors into warnings" OFF)
 
 if(NOT SILKWORM_HAS_PARENT)
   include(cmake/conan.cmake)

cmake/compiler_warnings.cmake

@@ -33,6 +33,11 @@ elseif((CMAKE_CXX_COMPILER_ID STREQUAL "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" MAT
   add_compile_options(-Wtype-limits -Wformat=2)
   add_compile_options(-Wno-missing-field-initializers)
 
+  if(SILKWORM_ALLOW_UNUSED_VAR_WARNINGS)
+    add_compile_options(-Wno-error=unused-parameter)
+    add_compile_options(-Wno-error=unused-variable)
+  endif()
+
   if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     add_compile_options(-Wduplicated-cond -Wduplicated-branches -Wlogical-op)
     add_compile_options(-Wno-attributes)