Don't set target_link_libraries on disabled group test

Author: jckarter

tests/CMakeLists.txt

@@ -159,6 +159,7 @@ set(DISPATCH_C_TESTS
 # Tests that usually pass, but occasionally fail.
 # Excluded by default for purposes of Swift CI
 if(EXTENDED_TEST_SUITE)
+ # When dispatch_group is reenabled here, also remove the if(EXTENDED_TEST_SUITE) condition below
  list(APPEND DISPATCH_C_TESTS
  priority
  concur
@@ -205,7 +206,10 @@ add_unit_test(dispatch_plusplus SOURCES dispatch_plusplus.cpp)
 if(WIN32)
  target_link_libraries(dispatch_io_net PRIVATE WS2_32)
 else()
- target_link_libraries(dispatch_group PRIVATE m)
+ # When dispatch_group is reenabled above, remove this
+ if(EXTENDED_TEST_SUITE)
+ target_link_libraries(dispatch_group PRIVATE m)
+ endif()
  target_link_libraries(dispatch_timer_short PRIVATE m)
 endif()