Genex-LINK_GROUP: Add feature RESCAN

Feature RESCAN can be used to manage circular references between
static libraries.

Modules/Platform/Linux.cmake

@@ -19,6 +19,14 @@ foreach(type SHARED_LIBRARY SHARED_MODULE EXE)
   set(CMAKE_${type}_LINK_DYNAMIC_C_FLAGS "-Wl,-Bdynamic")
 endforeach()
 
+
+# Features for LINK_GROUP generator expression
+## RESCAN: request the linker to rescan static libraries until there is
+## no pending undefined symbols
+set(CMAKE_LINK_GROUP_USING_RESCAN "LINKER:--start-group" "LINKER:--end-group")
+set(CMAKE_LINK_GROUP_USING_RESCAN_SUPPORTED TRUE)
+
+
 # Debian policy requires that shared libraries be installed without
 # executable permission.  Fedora policy requires that shared libraries
 # be installed with the executable permission.  Since the native tools

Modules/Platform/SunOS.cmake

@@ -7,6 +7,16 @@ if(CMAKE_SYSTEM MATCHES "SunOS-4")
   set(CMAKE_SHARED_LIBRARY_RUNTIME_C_FLAG_SEP ":")
 endif()
 
+
+# Features for LINK_GROUP generator expression
+if (CMAKE_SYSTEM_VERSION VERSION_GREATER "5.9")
+  ## RESCAN: request the linker to rescan static libraries until there is
+  ## no pending undefined symbols
+  set(CMAKE_LINK_GROUP_USING_RESCAN "LINKER:-z,rescan-start" "LINKER:-z,rescan-end")
+  set(CMAKE_LINK_GROUP_USING_RESCAN_SUPPORTED TRUE)
+endif()
+
+
 include(Platform/UnixPaths)
 
 list(APPEND CMAKE_SYSTEM_PREFIX_PATH

Modules/Platform/Windows-GNU.cmake

@@ -44,6 +44,14 @@ if("${_help}" MATCHES "GNU ld .* 2\\.1[1-6]")
   set(__WINDOWS_GNU_LD_RESPONSE 0)
 endif()
 
+
+# Features for LINK_GROUP generator expression
+## RESCAN: request the linker to rescan static libraries until there is
+## no pending undefined symbols
+set(CMAKE_LINK_GROUP_USING_RESCAN "LINKER:--start-group" "LINKER:--end-group")
+set(CMAKE_LINK_GROUP_USING_RESCAN_SUPPORTED TRUE)
+
+
 macro(__windows_compiler_gnu lang)
 
   # Create archiving rules to support large object file lists for static libraries.