build: fixed building on macOS

System/CMakeLists.txt

@@ -11,6 +11,17 @@ endif()
 
 message(STATUS "Dewar kernel: Building for architecture '${ARCH}'")
 
+set(TERMOS_OBJCOPY objcopy)
+if(APPLE)
+    find_program(TERMOS_LD_LLD NAMES ld.lld HINTS /usr/local/bin /opt/homebrew/bin REQUIRED)
+    find_program(TERMOS_OBJCOPY NAMES llvm-objcopy objcopy HINTS /usr/local/opt/llvm/bin /opt/homebrew/opt/llvm/bin REQUIRED)
+    set(CMAKE_C_LINK_FLAGS "")
+    set(CMAKE_ASM_NASM_COMPILE_OBJECT
+        "<CMAKE_ASM_NASM_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -MD <DEP_FILE> -MT <DEP_TARGET> -f elf64 -o <OBJECT> <SOURCE>")
+    set(CMAKE_C_LINK_EXECUTABLE
+        "${TERMOS_LD_LLD} <CMAKE_C_LINK_FLAGS> <LINK_FLAGS> <OBJECTS> -o <TARGET> <LINK_LIBRARIES>")
+endif()
+
 
 file(GLOB_RECURSE KERNEL_SOURCES CMAKE_CONFIGURE_DEPENDS
     "src/kmain.c"
@@ -30,6 +41,7 @@ file(GLOB_RECURSE KERNEL_SOURCES CMAKE_CONFIGURE_DEPENDS
 )
 
 add_executable(kernel ${KERNEL_SOURCES})
+set_target_properties(kernel PROPERTIES NASM_OBJ_FORMAT elf64)
 
 target_include_directories(kernel PRIVATE
     "${CMAKE_CURRENT_SOURCE_DIR}/../common"
@@ -40,6 +52,7 @@ target_include_directories(kernel PRIVATE
 
 target_compile_options(kernel PRIVATE
     $<$<COMPILE_LANGUAGE:C>:
+        $<$<BOOL:${APPLE}>:--target=x86_64-none-elf>
         -ffreestanding
         -mno-red-zone
         -fno-stack-protector
@@ -49,6 +62,7 @@ target_compile_options(kernel PRIVATE
         -g
         -mno-sse -mno-sse2 -msoft-float
     >
+    $<$<AND:$<BOOL:${APPLE}>,$<COMPILE_LANGUAGE:ASM>>:--target=x86_64-none-elf>
 )
 
 target_link_options(kernel PRIVATE
@@ -65,6 +79,8 @@ set_target_properties(kernel PROPERTIES
 )
 
 add_custom_command(TARGET kernel POST_BUILD
-    COMMAND objcopy -O binary $<TARGET_FILE:kernel> $<TARGET_FILE_DIR:kernel>/kernel.bin
+    COMMAND ${CMAKE_COMMAND} -E env
+        "PATH=/usr/local/opt/llvm/bin:/opt/homebrew/opt/llvm/bin:$ENV{PATH}"
+        llvm-objcopy -O binary $<TARGET_FILE:kernel> $<TARGET_FILE_DIR:kernel>/kernel.bin
     COMMENT "Generating raw binary kernel.bin..."
 )