[cmake] remove directory scoped add_definitions calls (#4112)

These won't work well if a parent project includes openthread as a
subproject, and aren't as well abstracted as the target-based
definitions.

CMakeLists.txt

@@ -43,9 +43,9 @@ execute_process(
 )
 set(OT_VERSION "${__version}")
 
-add_definitions(
-    -DPACKAGE_NAME="OPENTHREAD"
-    -DPACKAGE_VERSION="${OT_VERSION}"
+list(APPEND OT_PRIVATE_DEFINES
+    "PACKAGE_NAME=\"OPENTHREAD\""
+    "PACKAGE_VERSION=\"${OT_VERSION}\""
 )
 
 set(OT_PLATFORM "none" CACHE STRING "Target platform chosen by the user at configure time")
@@ -77,12 +77,14 @@ if(NOT OT_PLATFORM MATCHES "none")
     include("${OT_ROOT_DIR}/examples/platforms/${OT_PLATFORM}/platform.cmake")
 endif()
 
+list(APPEND OT_PRIVATE_DEFINES ${OT_PLATFORM_DEFINES})
+
 if(OT_BUILTIN_MBEDTLS)
     list(APPEND OT_PRIVATE_INCLUDES ${OT_ROOT_DIR}/third_party/mbedtls)
     list(APPEND OT_PRIVATE_INCLUDES ${OT_ROOT_DIR}/third_party/mbedtls/repo/include)
 
-    add_definitions(
-        -DMBEDTLS_CONFIG_FILE="mbedtls-config.h"
+    list(APPEND OT_PRIVATE_DEFINES
+        "MBEDTLS_CONFIG_FILE=\"mbedtls-config.h\""
     )
 endif()
 

examples/platforms/cc2538/CMakeLists.txt

@@ -42,6 +42,8 @@ add_library(openthread-cc2538
 
 target_link_libraries(openthread-cc2538 PRIVATE openthread-platform-utils)
 
+target_compile_definitions(openthread-cc2538 PUBLIC ${OT_PLATFORM_DEFINES})
+
 target_include_directories(openthread-cc2538 PRIVATE
     ${OT_PUBLIC_INCLUDES}
     ${OT_PRIVATE_INCLUDES}

examples/platforms/cc2538/platform.cmake

@@ -26,10 +26,10 @@
 #  POSSIBILITY OF SUCH DAMAGE.
 #
 
-add_definitions(
-    -DOPENTHREAD_PROJECT_CORE_CONFIG_FILE="openthread-core-cc2538-config.h"
-    -DOPENTHREAD_CORE_CONFIG_PLATFORM_CHECK_FILE="openthread-core-cc2538-config-check.h"
-    -DOPENTHREAD_CONFIG_NCP_UART_ENABLE=1
+list(APPEND OT_PLATFORM_DEFINES
+    "OPENTHREAD_PROJECT_CORE_CONFIG_FILE=\"openthread-core-cc2538-config.h\""
+    "OPENTHREAD_CORE_CONFIG_PLATFORM_CHECK_FILE=\"openthread-core-cc2538-config-check.h\""
+    "OPENTHREAD_CONFIG_NCP_UART_ENABLE=1"
 )
 
 set(common_c_flags "-mcpu=cortex-m3 -mfloat-abi=soft")

examples/platforms/posix/CMakeLists.txt

@@ -50,6 +50,8 @@ endif()
 
 target_link_libraries(openthread-posix PRIVATE openthread-platform-utils)
 
+target_compile_definitions(openthread-posix PUBLIC ${OT_PLATFORM_DEFINES})
+
 target_include_directories(openthread-posix PRIVATE
     ${OT_PUBLIC_INCLUDES}
     ${OT_PRIVATE_INCLUDES}

examples/platforms/posix/platform.cmake

@@ -26,10 +26,10 @@
 #  POSSIBILITY OF SUCH DAMAGE.
 #
 
-add_definitions(
-    -DOPENTHREAD_PROJECT_CORE_CONFIG_FILE="openthread-core-posix-config.h"
-    -DOPENTHREAD_EXAMPLES_POSIX=1
-    -DOPENTHREAD_CONFIG_NCP_UART_ENABLE=1
+list(APPEND OT_PLATFORM_DEFINES
+    "OPENTHREAD_PROJECT_CORE_CONFIG_FILE=\"openthread-core-posix-config.h\""
+    "OPENTHREAD_EXAMPLES_POSIX=1"
+    "OPENTHREAD_CONFIG_NCP_UART_ENABLE=1"
 )
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DOPENTHREAD_POSIX=1")