Merge bitcoin#30778: build: Fix linking for fuzz target when buildi…

…ng with MSan

787dfaf ci: Do not override `-g -O1` set in `MSAN_FLAGS` (Hennadii Stepanov)
26c460a build: Fix linking for `fuzz` target when building with MSan (Hennadii Stepanov)

Pull request description:

  The first commit fixes bitcoin#30760.

  The second commit:
  1. Preserves `-g -O1` set in `MSAN_FLAGS`. Since configuration-specific flags override general flags, these are set to empty strings. A similar approach is used in the OSS-Fuzz repository.
  2. Sets the "Debug" build configuration when depends are built with `DEBUG=1`, ensuring that `linux_debug_CPPFLAGS` from depends are passed to the main build system.

ACKs for top commit:
  maflcko:
    review-only ACK 787dfaf
  fanquake:
    ACK 787dfaf - as a follow up it would be good to:

Tree-SHA512: c324390d1dbda30f82025d8482ddb0cfa0395f9ba225a2ddce05a123c65e0622a6a1d5f0fa03f09e21d62792431cf3da5c49e41a3ac7f7a958d0392a0430f29c

ci/test/00_setup_env_native_fuzz_with_msan.sh

@@ -17,8 +17,12 @@ export PACKAGES="ninja-build"
 # BDB generates false-positives and will be removed in future
 export DEP_OPTS="DEBUG=1 NO_BDB=1 NO_QT=1 CC=clang CXX=clang++ CFLAGS='${MSAN_FLAGS}' CXXFLAGS='${MSAN_AND_LIBCXX_FLAGS}'"
 export GOAL="install"
+# Setting CMAKE_{C,CXX}_FLAGS_DEBUG flags to an empty string ensures that the flags set in MSAN_FLAGS remain unaltered.
 # _FORTIFY_SOURCE is not compatible with MSAN.
 export BITCOIN_CONFIG="\
+ -DCMAKE_BUILD_TYPE=Debug \
+ -DCMAKE_C_FLAGS_DEBUG='' \
+ -DCMAKE_CXX_FLAGS_DEBUG='' \
  -DBUILD_FOR_FUZZING=ON \
  -DSANITIZERS=fuzzer,memory \
  -DAPPEND_CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE -U_FORTIFY_SOURCE' \

ci/test/00_setup_env_native_msan.sh

@@ -17,8 +17,15 @@ export PACKAGES="ninja-build"
 # BDB generates false-positives and will be removed in future
 export DEP_OPTS="DEBUG=1 NO_BDB=1 NO_QT=1 CC=clang CXX=clang++ CFLAGS='${MSAN_FLAGS}' CXXFLAGS='${MSAN_AND_LIBCXX_FLAGS}'"
 export GOAL="install"
+# Setting CMAKE_{C,CXX}_FLAGS_DEBUG flags to an empty string ensures that the flags set in MSAN_FLAGS remain unaltered.
 # _FORTIFY_SOURCE is not compatible with MSAN.
-export BITCOIN_CONFIG="-DSANITIZERS=memory -DAPPEND_CPPFLAGS='-U_FORTIFY_SOURCE'"
+export BITCOIN_CONFIG="\
+ -DCMAKE_BUILD_TYPE=Debug \
+ -DCMAKE_C_FLAGS_DEBUG='' \
+ -DCMAKE_CXX_FLAGS_DEBUG='' \
+ -DSANITIZERS=memory \
+ -DAPPEND_CPPFLAGS='-U_FORTIFY_SOURCE' \
+"
 export USE_MEMORY_SANITIZER="true"
 export RUN_FUNCTIONAL_TESTS="false"
 export CCACHE_MAXSIZE=250M

src/test/fuzz/CMakeLists.txt

@@ -132,6 +132,7 @@ target_link_libraries(fuzz
   test_fuzz
   bitcoin_cli
   bitcoin_common
+  bitcoin_util
   minisketch
   leveldb
   univalue