fix(profiling): explicitly link with thread library (#10994)

python:3.11-bookworm image for aarch64 has `pthread_atfork` in static
libpthread.a not in libpthread.so so need to explicitly link for those
cases. Otherwise, we get undefined symbol `pthread_atfork`.


## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [ ] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
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[release branch maintenance
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ddtrace/internal/datadog/profiling/dd_wrapper/CMakeLists.txt

@@ -21,6 +21,13 @@ include(FindCppcheck)
 include(FindInfer)
 include(CheckSymbolExists)
 
+set(THREADS_PREFER_PTHREAD_FLAG ON)
+find_package(Threads REQUIRED)
+
+if(NOT Threads_FOUND OR NOT CMAKE_USE_PTHREADS_INIT)
+ message(FATAL_ERROR "pthread compatible library not found")
+endif()
+
 # Library sources
 add_library(
  dd_wrapper SHARED
@@ -44,7 +51,7 @@ target_compile_features(dd_wrapper PUBLIC cxx_std_17)
 
 target_include_directories(dd_wrapper PRIVATE include ${Datadog_INCLUDE_DIRS})
 
-target_link_libraries(dd_wrapper PRIVATE ${Datadog_LIBRARIES})
+target_link_libraries(dd_wrapper PRIVATE ${Datadog_LIBRARIES} Threads::Threads)
 
 # Figure out the suffix. Try to approximate the cpython way of doing things. C library
 check_symbol_exists(__GLIBC__ "features.h" HAVE_GLIBC)

ddtrace/internal/datadog/profiling/stack_v2/CMakeLists.txt

@@ -22,11 +22,19 @@ include(FindCppcheck)
 add_subdirectory(../dd_wrapper ${CMAKE_CURRENT_BINARY_DIR}/../dd_wrapper_build)
 
 find_package(Python3 COMPONENTS Interpreter Development)
+
 # Make sure we have necessary Python variables
 if(NOT Python3_INCLUDE_DIRS)
  message(FATAL_ERROR "Python3_INCLUDE_DIRS not found")
 endif()
 
+set(THREADS_PREFER_PTHREAD_FLAG ON)
+find_package(Threads REQUIRED)
+
+if(NOT Threads_FOUND OR NOT CMAKE_USE_PTHREADS_INIT)
+ message(FATAL_ERROR "pthread compatible library not found")
+endif()
+
 # Add echion
 set(ECHION_COMMIT
  "9d5bcc5867d7aefff73c837adcba4ef46eecebc6"
@@ -70,9 +78,9 @@ target_compile_definitions(${EXTENSION_NAME} PRIVATE UNWIND_NATIVE_DISABLE)
 # warning(push, 0 then pop for the same effect.
 target_include_directories(
  ${EXTENSION_NAME} PRIVATE .. # include dd_wrapper from the root in order to make its paths transparent in the code
-  include)
+ include)
 target_include_directories(${EXTENSION_NAME} SYSTEM PRIVATE ${echion_SOURCE_DIR} ${Python3_INCLUDE_DIRS}
-  include/vendored include/util)
+ include/vendored include/util)
 
 # Echion sources need to be given the current platform
 if(WIN32)
@@ -92,11 +100,10 @@ set_target_properties(${EXTENSION_NAME} PROPERTIES SUFFIX "")
 # typical.
 set_target_properties(${EXTENSION_NAME} PROPERTIES INSTALL_RPATH "$ORIGIN/..")
 
+target_link_libraries(${EXTENSION_NAME} PRIVATE dd_wrapper Threads::Threads)
+
 if(Python3_LIBRARIES)
- target_link_libraries(${EXTENSION_NAME} PRIVATE dd_wrapper ${Python3_LIBRARIES})
-else()
- # for manylinux builds
- target_link_libraries(${EXTENSION_NAME} PRIVATE dd_wrapper)
+ target_link_libraries(${EXTENSION_NAME} PRIVATE ${Python3_LIBRARIES})
 endif()
 
 # Extensions are built as dynamic libraries, so PIC is required.

releasenotes/notes/profiling-pthread-aarch64-d4548fd1842d0665.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+ - |
+ profiling: fixes an issue where stack v2 couldn't be enabled as pthread
+ was not properly linked on some debian based images for aarch64 architecture.
+