Add basic UEFI support

cmake/Platform/UEFI.cmake

@@ -0,0 +1,13 @@
+# References:
+# - https://gitlab.kitware.com/cmake/cmake/-/merge_requests/6630
+# - https://gitlab.kitware.com/cmake/cmake/-/issues/16538
+# - https://kubasejdak.com/how-to-cross-compile-for-embedded-with-cmake-like-a-champ
+
+include(Platform/Generic)
+
+set(CMAKE_EXECUTABLE_SUFFIX ".efi")
+set(CMAKE_SHARED_LIBRARY_SUFFIX ".efi")
+set(CMAKE_SHARED_LIBRARY_PREFIX "")
+
+# UEFI APIs might expect 16-bit wchar_t
+add_compile_options(-fshort-wchar)

cmake/zig-toolchain-uefi64.cmake

@@ -0,0 +1,2 @@
+set(ZIG_TARGET "x86_64-uefi-gnu")
+include(${CMAKE_CURRENT_LIST_DIR}/zig-toolchain.cmake)

cmake/zig-toolchain.cmake

@@ -20,6 +20,10 @@ elseif(ZIG_OS STREQUAL "macos")
     set(CMAKE_SYSTEM_NAME "Darwin")
 elseif(ZIG_OS STREQUAL "freestanding")
     set(CMAKE_SYSTEM_NAME "Generic")
+elseif(ZIG_OS STREQUAL "uefi")
+    set(CMAKE_SYSTEM_NAME "UEFI")
+    # Fix compiler detection (lld-link: error: <root>: undefined symbol: EfiMain)
+    set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
 else()
     # NOTE: If this happens, add a new case with one of the following system names:
     # https://cmake.org/cmake/help/latest/variable/CMAKE_SYSTEM_NAME.html#system-names-known-to-cmake
@@ -42,3 +46,6 @@ endif()
 set(CMAKE_AR "${CMAKE_CURRENT_LIST_DIR}/zig-ar${SCRIPT_SUFFIX}")
 set(CMAKE_RANLIB "${CMAKE_CURRENT_LIST_DIR}/zig-ranlib${SCRIPT_SUFFIX}")
 set(CMAKE_RC_COMPILER "${CMAKE_CURRENT_LIST_DIR}/zig-rc${SCRIPT_SUFFIX}")
+
+# Add custom UEFI platform to module path
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}")