Merge #51: cmake: Generate obj/build.h header

5c2c0f3 cmake: Generate `obj/build.h` header (Hennadii Stepanov)

Pull request description:

ACKs for top commit:
  theuni:
    ACK 5c2c0f3

Tree-SHA512: 78bb55034c1df587e68485a3137228b37fc79ace293516b386e3e7ff0796e804a680b455cff80cb71bb6af3d1d86e5d82286b20a4662cd72d8e1396417fc21cb

src/CMakeLists.txt

@@ -8,6 +8,25 @@ configure_file(${CMAKE_SOURCE_DIR}/cmake/bitcoin-config.h.in config/bitcoin-conf
 add_compile_definitions(HAVE_CONFIG_H)
 include_directories(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
 
+# After the transition from Autotools to CMake, the obj/ subdirectory
+# could be dropped as its only purpose was to separate a generated header
+# from source files.
+add_custom_target(generate_build_info
+  BYPRODUCTS ${PROJECT_BINARY_DIR}/src/obj/build.h
+  COMMAND ${CMAKE_COMMAND} -E make_directory ${PROJECT_BINARY_DIR}/src/obj
+  COMMAND ${PROJECT_SOURCE_DIR}/share/genbuild.sh ${PROJECT_BINARY_DIR}/src/obj/build.h ${PROJECT_SOURCE_DIR}
+  COMMENT "Generating obj/build.h"
+  VERBATIM
+)
+add_library(bitcoin_clientversion OBJECT EXCLUDE_FROM_ALL
+  clientversion.cpp
+)
+target_compile_definitions(bitcoin_clientversion
+  PRIVATE
+    HAVE_BUILD_INFO
+)
+add_dependencies(bitcoin_clientversion generate_build_info)
+
 add_subdirectory(crypto)
 add_subdirectory(univalue)
 add_subdirectory(util)

src/util/CMakeLists.txt

@@ -33,7 +33,6 @@ add_library(bitcoin_util STATIC EXCLUDE_FROM_ALL
   time.cpp
   tokenpipe.cpp
   ../chainparamsbase.cpp
-  ../clientversion.cpp
   ../logging.cpp
   ../random.cpp
   ../randomenv.cpp
@@ -52,6 +51,7 @@ target_compile_definitions(bitcoin_util
 target_link_libraries(bitcoin_util
   PRIVATE
     core
+    bitcoin_clientversion
     bitcoin_crypto
     Threads::Threads
     $<$<BOOL:${MINGW}>:ws2_32>