CMake: carry over some nuances from autotools test config

Port over test-specific compilation flags and support for
lenient deadlines for running in the Swift CI from Makefile.am

Author: dgrove-oss

tests/CMakeLists.txt

@@ -74,6 +74,9 @@ function(add_unit_test name)
                                ${CMAKE_CURRENT_BINARY_DIR}
                                ${CMAKE_CURRENT_SOURCE_DIR}
                                ${CMAKE_SOURCE_DIR})
+  if(CMAKE_SWIFT_COMPILER)
+	target_compile_options(${name} PRIVATE -DLENIENT_DEADLINES=1)
+  endif()
   if(WITH_BLOCKS_RUNTIME)
     target_include_directories(${name}
                                SYSTEM BEFORE PRIVATE
@@ -154,3 +157,9 @@ endforeach()
 target_link_libraries(dispatch_group PRIVATE m)
 target_link_libraries(dispatch_timer_short PRIVATE m)
 
+# test-specific compiler flags
+target_compile_options(dispatch_c99 PRIVATE -std=c99)
+
+# test-specific compiler flags (for currently disabled tests)
+#add_unit_test(dispatch_priority2 SOURCES dispatch_priority.c)
+#target_compile_options(dispatch_priority2, PRIVATE -DUSE_SET_TARGET_QUEUE=1)