Make $<LINK_ONLY> available to projects (#14751)

Previously this generator expression was used internally by the
target_link_libraries command to honor private linking requirements of
static libraries in their INTERFACE_LINK_LIBRARIES.  Remove the check
that limits $<LINK_ONLY> to this use case to make it available for
project code to use too.

8 files changed, 35 insertions, 2 deletions

diff --git a/Tests/InterfaceLinkLibraries/CMakeLists.txt b/Tests/InterfaceLinkLibraries/CMakeLists.txt
index bd0cf74..9e14c44 100644
--- a/Tests/InterfaceLinkLibraries/CMakeLists.txt
+++ b/Tests/InterfaceLinkLibraries/CMakeLists.txt
@@ -9,6 +9,9 @@ target_compile_definitions(foo_shared INTERFACE FOO_LIBRARY)
 add_library(bar_shared SHARED bar_vs6_1.cpp)
 target_compile_definitions(bar_shared INTERFACE BAR_LIBRARY)
 set_property(TARGET bar_shared APPEND PROPERTY INTERFACE_LINK_LIBRARIES foo_shared)
+add_library(zot_shared SHARED zot_vs6_1.cpp)
+target_compile_definitions(zot_shared INTERFACE ZOT_LIBRARY)
+set_property(TARGET bar_shared APPEND PROPERTY INTERFACE_LINK_LIBRARIES $<LINK_ONLY:zot_shared>)
 
 add_executable(shared_test main_vs6_1.cpp)
 set_property(TARGET shared_test APPEND PROPERTY LINK_LIBRARIES bar_shared)
@@ -18,6 +21,9 @@ target_compile_definitions(foo_static INTERFACE FOO_LIBRARY)
 add_library(bar_static STATIC bar_vs6_2.cpp)
 target_compile_definitions(bar_static INTERFACE BAR_LIBRARY)
 set_property(TARGET bar_static APPEND PROPERTY INTERFACE_LINK_LIBRARIES foo_static)
+add_library(zot_static STATIC zot_vs6_2.cpp)
+target_compile_definitions(zot_static INTERFACE ZOT_LIBRARY)
+set_property(TARGET bar_static APPEND PROPERTY INTERFACE_LINK_LIBRARIES $<LINK_ONLY:zot_static>)
 
 add_executable(static_test main_vs6_2.cpp)
 set_property(TARGET static_test APPEND PROPERTY LINK_LIBRARIES bar_static)
@@ -31,6 +37,9 @@ target_compile_definitions(bar_shared_private INTERFACE BAR_LIBRARY)
 target_compile_definitions(bar_shared_private PRIVATE BAR_USE_BANG)
 set_property(TARGET bar_shared_private APPEND PROPERTY LINK_LIBRARIES bang_shared_private)
 set_property(TARGET bar_shared_private APPEND PROPERTY INTERFACE_LINK_LIBRARIES foo_shared_private)
+add_library(zot_shared_private SHARED zot_vs6_3.cpp)
+target_compile_definitions(zot_shared_private INTERFACE ZOT_LIBRARY)
+set_property(TARGET bar_shared_private APPEND PROPERTY INTERFACE_LINK_LIBRARIES $<LINK_ONLY:zot_shared_private>)
 
 add_executable(shared_private_test main_vs6_3.cpp)
 set_property(TARGET shared_private_test APPEND PROPERTY LINK_LIBRARIES bar_shared_private)
@@ -44,6 +53,9 @@ target_compile_definitions(bar_static_private INTERFACE BAR_LIBRARY)
 target_compile_definitions(bar_static_private PRIVATE BAR_USE_BANG)
 set_property(TARGET bar_static_private APPEND PROPERTY LINK_LIBRARIES bang_static_private)
 set_property(TARGET bar_static_private APPEND PROPERTY INTERFACE_LINK_LIBRARIES $<LINK_ONLY:bang_static_private> foo_static_private)
+add_library(zot_static_private STATIC zot_vs6_4.cpp)
+target_compile_definitions(zot_static_private INTERFACE ZOT_LIBRARY)
+set_property(TARGET bar_static_private APPEND PROPERTY INTERFACE_LINK_LIBRARIES $<LINK_ONLY:zot_static_private>)
 
 add_executable(InterfaceLinkLibraries main_vs6_4.cpp)
 set_property(TARGET InterfaceLinkLibraries APPEND PROPERTY LINK_LIBRARIES bar_static_private)
diff --git a/Tests/InterfaceLinkLibraries/main.cpp b/Tests/InterfaceLinkLibraries/main.cpp
index a54076a..6e1295a 100644
--- a/Tests/InterfaceLinkLibraries/main.cpp
+++ b/Tests/InterfaceLinkLibraries/main.cpp
@@ -11,9 +11,13 @@
 #error Unexpected BANG_LIBRARY
 #endif
 
-#include "bar.h"
+#ifdef ZOT_LIBRARY
+#error Unexpected ZOT_LIBRARY
+#endif
+
+#include "zot.h"
 
 int main(void)
 {
-  return foo() + bar();
+  return foo() + bar() + zot();
 }
diff --git a/Tests/InterfaceLinkLibraries/zot.cpp b/Tests/InterfaceLinkLibraries/zot.cpp
new file mode 100644
index 0000000..69462b0
--- /dev/null
+++ b/Tests/InterfaceLinkLibraries/zot.cpp
@@ -0,0 +1,6 @@
+#include "zot.h"
+
+int zot()
+{
+  return 0;
+}
diff --git a/Tests/InterfaceLinkLibraries/zot.h b/Tests/InterfaceLinkLibraries/zot.h
new file mode 100644
index 0000000..5e4fb1e
--- /dev/null
+++ b/Tests/InterfaceLinkLibraries/zot.h
@@ -0,0 +1,7 @@
+
+#include "bar.h"
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int zot();
diff --git a/Tests/InterfaceLinkLibraries/zot_vs6_1.cpp b/Tests/InterfaceLinkLibraries/zot_vs6_1.cpp
new file mode 100644
index 0000000..c588c5f
--- /dev/null
+++ b/Tests/InterfaceLinkLibraries/zot_vs6_1.cpp
@@ -0,0 +1 @@
+#include "zot.cpp"
diff --git a/Tests/InterfaceLinkLibraries/zot_vs6_2.cpp b/Tests/InterfaceLinkLibraries/zot_vs6_2.cpp
new file mode 100644
index 0000000..c588c5f
--- /dev/null
+++ b/Tests/InterfaceLinkLibraries/zot_vs6_2.cpp
@@ -0,0 +1 @@
+#include "zot.cpp"
diff --git a/Tests/InterfaceLinkLibraries/zot_vs6_3.cpp b/Tests/InterfaceLinkLibraries/zot_vs6_3.cpp
new file mode 100644
index 0000000..c588c5f
--- /dev/null
+++ b/Tests/InterfaceLinkLibraries/zot_vs6_3.cpp
@@ -0,0 +1 @@
+#include "zot.cpp"
diff --git a/Tests/InterfaceLinkLibraries/zot_vs6_4.cpp b/Tests/InterfaceLinkLibraries/zot_vs6_4.cpp
new file mode 100644
index 0000000..c588c5f
--- /dev/null
+++ b/Tests/InterfaceLinkLibraries/zot_vs6_4.cpp
@@ -0,0 +1 @@
+#include "zot.cpp"