AIX-GNU: Link shared libs with -brtl,-bnoipath (#13352)

We already use these flags with the XL toolchain.  Use them for GNU too.

Modules/Platform/AIX-GNU.cmake

@@ -21,5 +21,6 @@ set(__AIX_COMPILER_GNU 1)
 macro(__aix_compiler_gnu lang)
   set(CMAKE_SHARED_LIBRARY_RUNTIME_${lang}_FLAG "-Wl,-blibpath:")
   set(CMAKE_SHARED_LIBRARY_RUNTIME_${lang}_FLAG_SEP ":")
-  set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "${CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS} -Wl,-G")
+  set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "${CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS} -Wl,-G,-brtl,-bnoipath")
+  set(CMAKE_SHARED_LIBRARY_LINK_${lang}_FLAGS "-Wl,-brtl,-bnoipath,-bexpall")  # +s, flag for exe link to use shared lib
 endmacro()