Use all-keyword style in target_link_libraries()

When using builtin_openssl=ON, CMake erroneously exports the builtin
static libraries in ROOTConfig-targets.cmake, which causes problems with
dependent projects. In order to avoid this, we need Net and RHTTP to use
SSL as a private dependency. Since CMake requires target_link_libraries()
to either be all-plain (as before) or all-keyword (required to allow
PRIVATE linking), we need to move the build system to use all-keyword
linking only.

Fixes: ROOT-9532

cmake/modules/RootNewMacros.cmake

@@ -655,9 +655,9 @@ function(ROOT_LINKER_LIBRARY library)
       set_target_properties(${library} PROPERTIES  ${ROOT_LIBRARY_PROPERTIES} )
     endif()
     if(explicitlink OR ROOT_explicitlink_FOUND)
-      target_link_libraries(${library} ${ARG_LIBRARIES} ${ARG_DEPENDENCIES})
+      target_link_libraries(${library} PUBLIC ${ARG_LIBRARIES} ${ARG_DEPENDENCIES})
     else()
-      target_link_libraries(${library} ${ARG_LIBRARIES})
+      target_link_libraries(${library} PUBLIC ${ARG_LIBRARIES})
     endif()
   endif()
   if(TARGET G__${library})

core/metacling/src/CMakeLists.txt

@@ -104,7 +104,7 @@ if(MSVC)
 endif()
 
 if(APPLE)
-  target_link_libraries(Cling -Wl,-bind_at_load -Wl,-undefined -Wl,dynamic_lookup)
+  target_link_libraries(Cling PUBLIC -Wl,-bind_at_load -Wl,-undefined -Wl,dynamic_lookup)
 elseif(NOT MSVC)
-  target_link_libraries(Cling -Wl,--unresolved-symbols=ignore-in-object-files)
+  target_link_libraries(Cling PUBLIC -Wl,--unresolved-symbols=ignore-in-object-files)
 endif()

math/vecops/CMakeLists.txt

@@ -24,7 +24,7 @@ ROOT_STANDARD_LIBRARY_PACKAGE(ROOTVecOps
                               LIBRARIES Core)
 
 if(vdt)
-  target_link_libraries(ROOTVecOps Vdt::Vdt)
+  target_link_libraries(ROOTVecOps PUBLIC Vdt::Vdt)
 endif()
 
 target_compile_options(ROOTVecOps PRIVATE -O3 -ffast-math)

net/http/CMakeLists.txt

@@ -56,7 +56,7 @@ target_compile_definitions(RHTTP PUBLIC -DUSE_WEBSOCKET)
 
 if(ssl)
   target_compile_definitions(RHTTP PUBLIC -DNO_SSL_DL)
-  target_link_libraries(RHTTP ${OPENSSL_LIBRARIES})
+  target_link_libraries(RHTTP PRIVATE ${OPENSSL_LIBRARIES})
   if(OPENSSL_VERSION AND (${OPENSSL_VERSION} VERSION_EQUAL "1.1"))
     MESSAGE(STATUS "Use SSL API VERSION 1.1 for civetweb")
     target_compile_definitions(RHTTP PUBLIC -DOPENSSL_API_1_1)

net/net/CMakeLists.txt

@@ -32,5 +32,5 @@ ROOT_STANDARD_LIBRARY_PACKAGE(Net
                               DEPENDENCIES RIO)
 
 if(ssl)
-  target_link_libraries(Net ${OPENSSL_LIBRARIES} ${CRYPTLIBS})
+  target_link_libraries(Net PRIVATE ${OPENSSL_LIBRARIES} ${CRYPTLIBS})
 endif()