correct capitalization for libSDL2
skip OpenXR

Index: code/CMakeLists.txt
--- code/CMakeLists.txt.orig
+++ code/CMakeLists.txt
@@ -35,7 +35,7 @@ TARGET_LINK_LIBRARIES(code PUBLIC ${PNG_LIBS})
 TARGET_LINK_LIBRARIES(code PUBLIC ${JPEG_LIBS})
 TARGET_LINK_LIBRARIES(code PUBLIC lz4)
 
-TARGET_LINK_LIBRARIES(code PUBLIC sdl2)
+TARGET_LINK_LIBRARIES(code PUBLIC SDL2)
 
 if (FSO_BUILD_WITH_FFMPEG)
 	TARGET_LINK_LIBRARIES(code PUBLIC ffmpeg)
@@ -79,7 +79,7 @@ target_link_libraries(code PUBLIC hidapi::hidapi)
 
 target_link_libraries(code PUBLIC imgui)
 
-IF(NOT APPLE)
+IF(NOT APPLE AND NOT CMAKE_SYSTEM_NAME MATCHES "OpenBSD")
 	target_link_libraries(code PUBLIC OpenXR::openxr_loader)
 	target_include_directories(code PUBLIC OpenXR::Headers)
 ENDIF()
@@ -139,4 +139,4 @@ set_target_properties(code PROPERTIES XCODE_ATTRIBUTE_
 set_target_properties(code PROPERTIES XCODE_ATTRIBUTE_GCC_SYMBOLS_PRIVATE_EXTERN[variant=Debug] "NO")
 
 # Prevent GCC warnings in third-party BitOp... see GitHub #4366
-suppress_file_warnings(scripting/lua/bitop/bit.c)
\ No newline at end of file
+suppress_file_warnings(scripting/lua/bitop/bit.c)
