Merge bitcoin/bitcoin#30865: build: Skip secp256k1 ctime tests when t…

…ests are not being built

23eedc5 build: Skip secp256k1 ctime tests when tests are not being built (Hennadii Stepanov)

Pull request description:

  Fixes bitcoin/bitcoin#30791 (comment):
  > Building with a fuzz engine fails, because the ctime tests are auto-detected in cmake, based on whether or not valgrind-devel is installed or not.

ACKs for top commit:
  maflcko:
    re-review ACK 23eedc5
  fanquake:
    ACK 23eedc5

Tree-SHA512: bfc0f2798acd36be9c52073d578b42c002606c60ef3fe8ef633eaea4f5382a3e9765d31637e4c25d8b71fd70473b29c24af4732e55e5183f27b48725b61fa15b

src/CMakeLists.txt

@@ -49,6 +49,11 @@ set(SECP256K1_ENABLE_MODULE_RECOVERY ON CACHE BOOL "" FORCE)
 set(SECP256K1_BUILD_BENCHMARK OFF CACHE BOOL "" FORCE)
 set(SECP256K1_BUILD_TESTS ${BUILD_TESTS} CACHE BOOL "" FORCE)
 set(SECP256K1_BUILD_EXHAUSTIVE_TESTS ${BUILD_TESTS} CACHE BOOL "" FORCE)
+if(NOT BUILD_TESTS)
+  # Always skip the ctime tests, if we are building no other tests.
+  # Otherwise, they are built if Valgrind is available. See SECP256K1_VALGRIND.
+  set(SECP256K1_BUILD_CTIME_TESTS ${BUILD_TESTS} CACHE BOOL "" FORCE)
+endif()
 set(SECP256K1_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
 include(GetTargetInterface)
 # -fsanitize and related flags apply to both C++ and C,