Refactor CMake scripts to replace CONFIGURE_COMMAND with CMAKE_ARGS for better clarity and maintainability.

Author: allnes

cmake/libenvpp.cmake

@@ -15,7 +15,7 @@ ExternalProject_Add(ppc_libenvpp
         -DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}
         -DCMAKE_CXX_STANDARD_REQUIRED=ON
         -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
-        -DFMT_CONSTEVAL=inline
+        -DCMAKE_TOOLCHAIN_FILE=${CMAKE_SOURCE_DIR}/cmake/libenvpp_toolchain.cmake
         BUILD_COMMAND     "${CMAKE_COMMAND}" --build "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/build" --config ${CMAKE_BUILD_TYPE} --parallel
         INSTALL_COMMAND   "${CMAKE_COMMAND}" --install "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/build" --prefix "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/install"
 )
@@ -27,10 +27,10 @@ else()
     set(PPC_FMT_LIB_NAME fmt)
 endif()
 
-if(MSVC)
+if(WIN32)
     set(PPC_ENVPP_LIB_NAME libenvpp)
 else()
     set(PPC_ENVPP_LIB_NAME envpp)
-endif ()
+endif()
 
 add_compile_definitions(FMT_CONSTEVAL=inline)

cmake/libenvpp_toolchain.cmake

@@ -0,0 +1,3 @@
+# libenvpp_toolchain.cmake
+set(CMAKE_CXX_FLAGS_INIT "-DFMT_CONSTEVAL=inline")
+set(CMAKE_C_FLAGS_INIT "-DFMT_CONSTEVAL=inline")