chore(cmake): move kmod/bpf options under linux

Signed-off-by: Roberto Scolaro <roberto.scolaro21@gmail.com>

cmake/modules/engine_config.cmake

@@ -1,6 +1,4 @@
 option(CREATE_TEST_TARGETS "Enable make-targets for unit testing" ON)
-option(ENABLE_ENGINE_KMOD "Enable kernel module engine" ON)
-option(ENABLE_ENGINE_BPF "Enable bpf engine" ON)
 
 if(CREATE_TEST_TARGETS)
 	# Add engine only used for testing
@@ -10,16 +8,13 @@ endif()
 set(HAS_ENGINE_NODRIVER On)
 set(HAS_ENGINE_SAVEFILE On)
 set(HAS_ENGINE_SOURCE_PLUGIN On)
-set(HAS_ENGINE_KMOD Off)
-set(HAS_ENGINE_BPF Off)
 
 if(CMAKE_SYSTEM_NAME MATCHES "Linux")
-	if(ENABLE_ENGINE_KMOD)
-		set(HAS_ENGINE_KMOD On)
-	endif()
-	if(ENABLE_ENGINE_BPF)
-		set(HAS_ENGINE_BPF On)
-	endif()
+	option(ENABLE_ENGINE_KMOD "Enable kernel module engine" ON)
+	option(ENABLE_ENGINE_BPF "Enable bpf engine" ON)
+
+	set(HAS_ENGINE_KMOD ${ENABLE_ENGINE_KMOD})
+	set(HAS_ENGINE_BPF ${ENABLE_ENGINE_BPF})
 
 	option(BUILD_LIBSCAP_MODERN_BPF "Enable modern bpf probe" OFF)
 	if(BUILD_LIBSCAP_MODERN_BPF)