CMake: Don't build p3dconfig anymore

dconfig.cxx was recently deleted.

p3dconfig is now just an interface library, since it still
contains a header which we'd like on the search path of
libraries that use it.

dtool/metalibs/dtoolconfig/CMakeLists.txt

@@ -1,3 +1,3 @@
-set(DTOOLCONFIG_LINK_TARGETS p3prc p3dconfig p3interrogatedb)
+set(DTOOLCONFIG_LINK_TARGETS p3prc p3interrogatedb)
 add_metalib(p3dtoolconfig INIT init_libdtoolconfig dtoolconfig.h COMPONENTS ${DTOOLCONFIG_LINK_TARGETS})
 install(TARGETS p3dtoolconfig DESTINATION lib RUNTIME DESTINATION bin)

dtool/src/dconfig/CMakeLists.txt

@@ -1,16 +1,5 @@
-set(P3DCONFIG_HEADERS
-  config_dconfig.h dconfig.I dconfig.h)
+# Yes, INTERFACE: don't build it, there's no code!
+# We're only doing this to put the .h file on the path.
+add_library(p3dconfig INTERFACE)
 
-set(P3DCONFIG_SOURCES
-  config_dconfig.cxx dconfig.cxx)
-
-composite_sources(p3dconfig P3DCONFIG_SOURCES)
-
-add_component_library(p3dconfig NOINIT SYMBOL BUILDING_DTOOL_DCONFIG
-  ${P3DCONFIG_HEADERS} ${P3DCONFIG_SOURCES})
-target_link_libraries(p3dconfig p3prc)
-
-if(NOT BUILD_METALIBS)
-  install(TARGETS p3dconfig DESTINATION lib RUNTIME DESTINATION bin)
-endif()
-install(FILES ${P3DCONFIG_HEADERS} DESTINATION include/panda3d)
+install(FILES dconfig.h DESTINATION include/panda3d)

dtool/src/interrogatedb/CMakeLists.txt

@@ -39,7 +39,7 @@ composite_sources(p3interrogatedb P3INTERROGATEDB_SOURCES)
 
 add_component_library(p3interrogatedb NOINIT SYMBOL BUILDING_INTERROGATEDB
   ${P3INTERROGATEDB_HEADERS} ${P3INTERROGATEDB_SOURCES})
-target_link_libraries(p3interrogatedb p3dconfig)
+target_link_libraries(p3interrogatedb p3prc p3dconfig p3dtool)
 
 if(NOT BUILD_METALIBS)
   install(TARGETS p3interrogatedb DESTINATION lib RUNTIME DESTINATION bin)