Use add_compile_options instead of add_definitions where appropriate

src/CMakeLists.txt

@@ -12,12 +12,12 @@ endif()
 
 CHECK_CXX_COMPILER_FLAG(-pthread CXX_HAS_PTHREAD)
 if(CXX_HAS_PTHREAD)
-    add_definitions(-pthread)
+    add_compile_options(-pthread)
 endif()
 
 CHECK_CXX_COMPILER_FLAG(-ffast-math CXX_HAS_FFAST_MATH)
 if(CXX_HAS_FFAST_MATH)
-    add_definitions(-ffast-math)
+    add_compile_options(-ffast-math)
 endif()
 
 # asprintf on MacOS
@@ -177,28 +177,28 @@ set(WITH_BCM_VC FALSE)
 
 if(PLATFORM STREQUAL "rpiv1")
 	set(BCM_VC ON)
-	add_definitions(-march=armv6zk -mcpu=arm1176jzf-s -mtune=arm1176jzf-s -mfpu=vfp)
+	add_compile_options(-march=armv6zk -mcpu=arm1176jzf-s -mtune=arm1176jzf-s -mfpu=vfp)
 	enable_language(ASM)
 	list(APPEND rtl_airband_extra_sources rtl_airband_vfp.s)
 elseif(PLATFORM STREQUAL "rpiv2")
 	set(BCM_VC ON)
-	add_definitions(-march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard)
+	add_compile_options(-march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard)
 	enable_language(ASM)
 	list(APPEND rtl_airband_extra_sources rtl_airband_neon.s)
 elseif(PLATFORM STREQUAL "armv7-generic")
-	add_definitions(-march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard)
+	add_compile_options(-march=armv7-a -mfpu=neon-vfpv4 -mfloat-abi=hard)
 elseif(PLATFORM STREQUAL "armv8-generic")
-	add_definitions(-march=armv8-a+crc -mtune=cortex-a53)
+	add_compile_options(-march=armv8-a+crc -mtune=cortex-a53)
 elseif(PLATFORM STREQUAL "native")
 	CHECK_CXX_COMPILER_FLAG(-march=native CXX_HAS_MARCH_NATIVE)
 	if(CXX_HAS_MARCH_NATIVE)
-		add_definitions(-march=native)
+		add_compile_options(-march=native)
 	else()
 		message(FATAL_ERROR "Cannot build with PLATFORM=native: the compiler does not support -march=native option")
 	endif()
 	CHECK_CXX_COMPILER_FLAG(-mtune=native CXX_HAS_MTUNE_NATIVE)
 	if(CXX_HAS_MTUNE_NATIVE)
-		add_definitions(-mtune=native)
+		add_compile_options(-mtune=native)
 	else()
 		message(FATAL_ERROR "Cannot build with PLATFORM=native: the compiler does not support -mtune=native option")
 	endif()