Add a flag to disable the inclusion of <format> and the provision for std::formatter specializations

CMakeLists.txt

@@ -306,6 +306,10 @@ target_compile_features(
 
 target_compile_definitions(${target_name} PRIVATE NOMINMAX)
 
+if(NOT CPPTRACE_STD_FORMAT)
+  target_compile_definitions(${target_name} PUBLIC CPPTRACE_NO_STD_FORMAT)
+endif()
+
 if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
   SET(CMAKE_C_ARCHIVE_FINISH   "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
   SET(CMAKE_CXX_ARCHIVE_FINISH "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")

README.md

@@ -952,6 +952,8 @@ Other useful configurations:
 - `CPPTRACE_INSTALL_CMAKEDIR`: Override for the installation path for the cmake configs.
 - `CPPTRACE_USE_EXTERNAL_LIBDWARF=On/Off`: Get libdwarf from `find_package` rather than `FetchContent`.
 - `CPPTRACE_POSITION_INDEPENDENT_CODE=On/Off`: Compile the library as a position independent code (PIE). Defaults to On.
+- `CPPTRACE_STD_FORMAT=On/Off`: Control inclusion of `<format>` and provision of `std::formatter` specializations by
+  cpptrace.hpp. This can also be controlled with the macro `CPPTRACE_NO_STD_FORMAT`.
 
 Testing:
 - `CPPTRACE_BUILD_TESTING` Build small demo and test program

cmake/OptionVariables.cmake

@@ -171,6 +171,7 @@ option(CPPTRACE_SANITIZER_BUILD "" OFF)
 option(CPPTRACE_WERROR_BUILD "" OFF)
 option(CPPTRACE_POSITION_INDEPENDENT_CODE "" ON)
 option(CPPTRACE_SKIP_UNIT "" OFF)
+option(CPPTRACE_STD_FORMAT "" ON)
 option(CPPTRACE_USE_EXTERNAL_GTEST "" OFF)
 set(CPPTRACE_ZSTD_REPO "https://github.com/facebook/zstd.git" CACHE STRING "")
 set(CPPTRACE_ZSTD_TAG "63779c798237346c2b245c546c40b72a5a5913fe" CACHE STRING "") # v1.5.5

include/cpptrace/cpptrace.hpp

@@ -34,11 +34,13 @@
 #  endif
 #endif
 
-#if __cplusplus >= 202002L
- #ifdef __has_include
-  #if __has_include(<format>)
-   #define CPPTRACE_STD_FORMAT
-   #include <format>
+#ifndef CPPTRACE_NO_STD_FORMAT
+ #if __cplusplus >= 202002L
+  #ifdef __has_include
+   #if __has_include(<format>)
+    #define CPPTRACE_STD_FORMAT
+    #include <format>
+   #endif
   #endif
  #endif
 #endif