cmake: unittest: ensure unit_testing platform uses 64-bit time_t

Use a 64-bit time_t on the unit_testing platform.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

Author: cfriedt

cmake/modules/unittest.cmake

@@ -96,8 +96,8 @@ if(M64_MODE)
 set (CMAKE_C_FLAGS "-m64")
 set (CMAKE_CXX_FLAGS "-m64")
 else()
-set (CMAKE_C_FLAGS "-m32") #deprecated on macOS
-set (CMAKE_CXX_FLAGS "-m32") #deprecated on macOS
+set (CMAKE_C_FLAGS "-m32 -D__USE_TIME_BITS64=1") #deprecated on macOS
+set (CMAKE_CXX_FLAGS "-m32 -D__USE_TIME_BITS64=1") #deprecated on macOS
 endif(M64_MODE)
 
 endif()