Merge #184: cmake: Add user-defined APPEND_{CPP,C,CXX,LD}FLAGS (take 2)

a9dc2c1 cmake: Dispaly `APPEND_{CPP,C,CXX,LD}FLAGS` in summary (Hennadii Stepanov)
bfadb6e cmake: Add `APPEND_{CPP,C,CXX,LD}FLAGS` cache variables (Hennadii Stepanov)

Pull request description:

  An alternative implementation of #157.

ACKs for top commit:
  vasild:
    ACK a9dc2c1

Tree-SHA512: 77fff64817c59153e4022390bed3a5db1eeb247ea916c99c582fcf18fe9e1f638aa2dd38121ebb5734339bf15d935a8b817083918020b944f2a0d72c76375e86

Author: hebasto

CMakeLists.txt

@@ -169,6 +169,14 @@ cmake_dependent_option(FUZZ "Build for fuzzing. Enabling this will disable all o
 
 option(INSTALL_MAN "Install man pages." ON)
 
+set(APPEND_CPPFLAGS "" CACHE STRING "Preprocessor flags that are appended to the flags added by the build system.")
+set(APPEND_CFLAGS "" CACHE STRING "C compiler flags that are appended to the flags added by the build system.")
+set(APPEND_CXXFLAGS "" CACHE STRING "(Objective) C++ compiler flags that are appended to the flags added by the build system.")
+set(APPEND_LDFLAGS "" CACHE STRING "Linker flags that are appended to the flags added by the build system.")
+string(APPEND CMAKE_CXX_COMPILE_OBJECT " ${APPEND_CPPFLAGS} ${APPEND_CXXFLAGS}")
+string(APPEND CMAKE_CXX_CREATE_SHARED_LIBRARY " ${APPEND_LDFLAGS}")
+string(APPEND CMAKE_CXX_LINK_EXECUTABLE " ${APPEND_LDFLAGS}")
+
 set(configure_warnings)
 
 include(CheckPIESupported)
@@ -630,15 +638,15 @@ endif()
 message("Cross compiling ....................... ${cross_status}")
 message("Preprocessor defined macros ........... ${definitions}")
 message("C compiler ............................ ${CMAKE_C_COMPILER_ID} ${CMAKE_C_COMPILER_VERSION}, ${CMAKE_C_COMPILER}")
-message("CFLAGS ................................ ${CMAKE_C_FLAGS}")
+message("CFLAGS ................................ ${CMAKE_C_FLAGS} ${APPEND_CPPFLAGS} ${APPEND_CFLAGS}")
 message("C++ compiler .......................... ${CMAKE_CXX_COMPILER_ID} ${CMAKE_CXX_COMPILER_VERSION}, ${CMAKE_CXX_COMPILER}")
-message("CXXFLAGS .............................. ${CMAKE_CXX_FLAGS}")
+message("CXXFLAGS .............................. ${CMAKE_CXX_FLAGS} ${APPEND_CPPFLAGS} ${APPEND_CXXFLAGS}")
 get_target_interface(common_compile_options core_interface COMPILE_OPTIONS)
 message("Common compile options ................ ${common_compile_options}")
 get_target_interface(common_link_options core_interface LINK_OPTIONS)
 message("Common link options ................... ${common_link_options}")
-message("Linker flags for executables .......... ${CMAKE_EXE_LINKER_FLAGS}")
-message("Linker flags for shared libraries ..... ${CMAKE_SHARED_LINKER_FLAGS}")
+message("Linker flags for executables .......... ${CMAKE_EXE_LINKER_FLAGS} ${APPEND_LDFLAGS}")
+message("Linker flags for shared libraries ..... ${CMAKE_SHARED_LINKER_FLAGS} ${APPEND_LDFLAGS}")
 print_config_flags()
 message("Attempt to harden executables ......... ${HARDENING}")
 message("Treat compiler warnings as errors ..... ${WERROR}")

cmake/secp256k1.cmake

@@ -9,6 +9,7 @@
 enable_language(C)
 set(CMAKE_C_STANDARD 90)
 set(CMAKE_C_EXTENSIONS OFF)
+string(APPEND CMAKE_C_COMPILE_OBJECT " ${APPEND_CPPFLAGS} ${APPEND_CFLAGS}")
 
 include(CheckCSourceCompiles)
 check_c_source_compiles("

src/qt/CMakeLists.txt

@@ -23,6 +23,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   set(CMAKE_OBJCXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
   set(CMAKE_OBJCXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
   set(CMAKE_OBJCXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL}")
+  string(APPEND CMAKE_OBJCXX_COMPILE_OBJECT " ${APPEND_CPPFLAGS} ${APPEND_CXXFLAGS}")
 endif()
 
 function(import_plugins target)