cmake: Add ccache support

cmake/ccache.cmake

@@ -0,0 +1,36 @@
+# Copyright (c) 2023-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+
+if(NOT MSVC)
+  find_program(CCACHE_EXECUTABLE ccache)
+  if(CCACHE_EXECUTABLE)
+    execute_process(
+      COMMAND readlink -f ${CMAKE_CXX_COMPILER}
+      OUTPUT_VARIABLE compiler_resolved_link
+      ERROR_QUIET
+      OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(CCACHE_EXECUTABLE STREQUAL compiler_resolved_link AND NOT WITH_CCACHE)
+      list(APPEND configure_warnings
+        "Disabling ccache was attempted using -DWITH_CCACHE=${WITH_CCACHE}, but ccache masquerades as the compiler."
+      )
+      set(WITH_CCACHE ON)
+    elseif(WITH_CCACHE)
+      list(APPEND CMAKE_C_COMPILER_LAUNCHER ${CCACHE_EXECUTABLE})
+      list(APPEND CMAKE_CXX_COMPILER_LAUNCHER ${CCACHE_EXECUTABLE})
+    endif()
+  else()
+    set(WITH_CCACHE OFF)
+  endif()
+  if(WITH_CCACHE)
+    try_append_cxx_flags("-fdebug-prefix-map=A=B" TARGET core_interface SKIP_LINK
+      IF_CHECK_PASSED "-fdebug-prefix-map=${PROJECT_SOURCE_DIR}=."
+    )
+    try_append_cxx_flags("-fmacro-prefix-map=A=B" TARGET core_interface SKIP_LINK
+      IF_CHECK_PASSED "-fmacro-prefix-map=${PROJECT_SOURCE_DIR}=."
+    )
+  endif()
+endif()
+
+mark_as_advanced(CCACHE_EXECUTABLE)