refactor: drop posix-uefi from bootloader

Replace the vendored POSIX-UEFI runtime with a small local EFI entry and header so the bootloader depends only on the UEFI interfaces it actually uses.

Made-with: Cursor

Bootloader/CMakeLists.txt

@@ -1,45 +1,32 @@
 cmake_minimum_required(VERSION 3.20)
 project(ksOS_bootloader LANGUAGES C ASM)
 
-set(UEFI_COMPILE_OPTIONS 
+set(UEFI_COMPILE_OPTIONS
     -std=c23
     -target aarch64-unknown-windows-msvc
     -Wall -Wextra
     -fno-builtin
 )
 
-set(POSIX_UEFI_SOURCES
-    Source/uefi/crt_aarch64.c 
-    Source/uefi/dirent.c
-    Source/uefi/qsort.c
-    Source/uefi/stat.c
-    Source/uefi/stdio.c
-    Source/uefi/stdlib.c
-    Source/uefi/string.c
-    Source/uefi/time.c
-    Source/uefi/unistd.c
+add_executable(BOOTAA64
+    Source/uefi/efi_entry.c
+    Source/main.c
 )
-
-add_library(posix_uefi_lib OBJECT ${POSIX_UEFI_SOURCES})
-target_compile_options(posix_uefi_lib PRIVATE ${UEFI_COMPILE_OPTIONS})
-target_include_directories(posix_uefi_lib PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/Source/uefi)
-
-
-add_executable(BOOTAA64 Source/main.c)
 target_compile_options(BOOTAA64 PRIVATE ${UEFI_COMPILE_OPTIONS})
-
-target_link_libraries(BOOTAA64 PRIVATE posix_uefi_lib)
+target_include_directories(BOOTAA64 PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/Source
+    ${CMAKE_CURRENT_SOURCE_DIR}/Source/uefi
+)
 
 target_link_options(BOOTAA64 PRIVATE
     -fuse-ld=lld
     -target aarch64-unknown-windows-msvc
     -nostdlib
     -Wl,-subsystem:efi_application
-    -Wl,-include:uefi_init
-    -Wl,-entry:uefi_init
+    -Wl,-entry:efi_main
 )
 
-set_target_properties(BOOTAA64 PROPERTIES 
+set_target_properties(BOOTAA64 PROPERTIES
     SUFFIX ".EFI"
     OUTPUT_NAME "BOOTAA64"
     RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/efi_bin"