Don't build internal OpenPGP parser when not using it

This regressed in d2be477 which tried
to shove the whole thing into the subdirectory for sawing off, but
it doesn't quite work like that - you can't quite depend on an option
that gets defined only if the option is defined...

CMakeLists.txt

@@ -28,6 +28,7 @@ option(WITH_AUDIT "Build with audit support" ON)
 option(WITH_FSVERITY "Build with fsverity support" OFF)
 option(WITH_IMAEVM "Build with IMA support" OFF)
 option(WITH_FAPOLICYD "Build with fapolicyd support" ON)
+option(WITH_INTERNAL_OPENPGP "Use internal OpenPGP parser (DEPRECATED)" OFF)
 
 set(RPM_CONFIGDIR "${CMAKE_INSTALL_PREFIX}/lib/rpm" CACHE PATH "rpm home")
 set(RPM_MACROSDIR "${RPM_CONFIGDIR}/macros.d")

rpmio/CMakeLists.txt

@@ -10,9 +10,8 @@ target_sources(librpmio PRIVATE
 target_compile_definitions(librpmio PRIVATE RPM_CONFIGDIR="${RPM_CONFIGDIR}")
 target_include_directories(librpmio PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
 
-add_subdirectory(rpmpgp_legacy)
-
 if (WITH_INTERNAL_OPENPGP)
+	add_subdirectory(rpmpgp_legacy)
 	target_link_libraries(librpmio PRIVATE rpmpgp_legacy)
 else()
 	pkg_check_modules(RPMSEQUOIA REQUIRED IMPORTED_TARGET rpm-sequoia>=1.4.0)

rpmio/rpmpgp_legacy/CMakeLists.txt

@@ -2,7 +2,6 @@
 # it can only be built as a part of rpm build tree.
 add_library(rpmpgp_legacy OBJECT)
 
-option(WITH_INTERNAL_OPENPGP "Use internal OpenPGP parser (DEPRECATED)" OFF)
 option(WITH_OPENSSL "Use openssl (instead of libgcrypt) for internal crypto" OFF)
 
 target_sources(rpmpgp_legacy PRIVATE