[Minor] Replace ADD_DEFINITIONS with ADD_COMPILE_OPTIONS

cmake/OSDep.cmake

 # Platform specific configuration
 IF(CMAKE_SYSTEM_NAME MATCHES "^.*BSD$|DragonFly")
-    ADD_DEFINITIONS(-DFREEBSD -D_BSD_SOURCE)
+    ADD_COMPILE_OPTIONS(-DFREEBSD -D_BSD_SOURCE)
     CONFIGURE_FILE(freebsd/rspamd.sh.in freebsd/rspamd @ONLY)
     MESSAGE(STATUS "Configuring for BSD system")
     # Find util library
 ENDIF()
 
 IF(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-    ADD_DEFINITIONS(-D_BSD_SOURCE -DDARWIN)
+    ADD_COMPILE_OPTIONS(-D_BSD_SOURCE -DDARWIN)
     SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "${CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS} -undefined dynamic_lookup")
     IF(ENABLE_LUAJIT MATCHES "ON")
         SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pagezero_size 10000 -image_base 100000000")
 ENDIF(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
 
 IF(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    ADD_DEFINITIONS(-D_GNU_SOURCE -DLINUX)
+    ADD_COMPILE_OPTIONS(-D_GNU_SOURCE -DLINUX)
     # Workaround with architecture specific includes
     #IF(IS_DIRECTORY "/usr/include/${CMAKE_SYSTEM_PROCESSOR}-linux-gnu/")
     #	INCLUDE_DIRECTORIES("/usr/include/${CMAKE_SYSTEM_PROCESSOR}-linux-gnu/")
         ENDIF(ENABLE_OPTIMIZATION MATCHES "ON")
     ENDIF("${CMAKE_C_COMPILER_ID}" MATCHES SunPro)
 
-    ADD_DEFINITIONS(-D__EXTENSIONS__ -DSOLARIS -D_POSIX_SOURCE -D_POSIX_C_SOURCE=200112)
+    ADD_COMPILE_OPTIONS(-D__EXTENSIONS__ -DSOLARIS -D_POSIX_SOURCE -D_POSIX_C_SOURCE=200112)
     LIST(APPEND CMAKE_REQUIRED_LIBRARIES rt)
     LIST(APPEND CMAKE_REQUIRED_LIBRARIES dl)
     LIST(APPEND CMAKE_REQUIRED_LIBRARIES resolv)

cmake/Openblas.cmake

         IF(NOT HAVE_CBLAS_H)
             MESSAGE(STATUS "Blas header cblas.h has not been found, use internal workaround")
         ELSE()
-            ADD_DEFINITIONS(-DHAVE_CBLAS_H)
+            ADD_COMPILE_OPTIONS(-DHAVE_CBLAS_H)
         ENDIF()
     ELSE()
-        ADD_DEFINITIONS(-DHAVE_CBLAS_H)
+        ADD_COMPILE_OPTIONS(-DHAVE_CBLAS_H)
     ENDIF()
-    ADD_DEFINITIONS(-DHAVE_CBLAS)
+    ADD_COMPILE_OPTIONS(-DHAVE_CBLAS)
 ENDIF(WITH_BLAS)