[cmake] avoid unnecessary rebuild when git commit id changes (#6881)

This commit removes the PACKAGE_VERSION definition from the global
config target so that when the git commit id is changed, only a few
sources will be re-compiled.

CMakeLists.txt

@@ -101,7 +101,6 @@ if(OT_PACKAGE_VERSION STREQUAL "")
     ot_git_version(OT_PACKAGE_VERSION)
     message(STATUS "Setting default package version: ${OT_PACKAGE_VERSION}")
 endif()
-target_compile_definitions(ot-config INTERFACE "PACKAGE_VERSION=\"${OT_PACKAGE_VERSION}\"")
 message(STATUS "Package Version: ${OT_PACKAGE_VERSION}")
 
 set(OT_THREAD_VERSION "1.2" CACHE STRING "Thread version chosen by the user at configure time")

src/cli/CMakeLists.txt

@@ -53,3 +53,7 @@ endif()
 if(OT_MTD)
     include(mtd.cmake)
 endif()
+
+set_property(SOURCE cli_joiner.cpp
+    APPEND PROPERTY COMPILE_DEFINITIONS "PACKAGE_VERSION=\"${OT_PACKAGE_VERSION}\""
+)

src/core/CMakeLists.txt

@@ -243,3 +243,7 @@ endif()
 if(OT_RCP)
     include(radio.cmake)
 endif()
+
+set_property(SOURCE api/instance_api.cpp
+    APPEND PROPERTY COMPILE_DEFINITIONS "PACKAGE_VERSION=\"${OT_PACKAGE_VERSION}\""
+)

src/ncp/CMakeLists.txt

@@ -69,3 +69,7 @@ endif()
 if(OT_RCP)
     include(radio.cmake)
 endif()
+
+set_property(SOURCE ncp_base_mtd.cpp
+    APPEND PROPERTY COMPILE_DEFINITIONS "PACKAGE_VERSION=\"${OT_PACKAGE_VERSION}\""
+)