Merge #7077: fix: add $(PTHREAD_FLAGS) to dash_util_LDFLAGS

f8d5c00 fix: add `$(PTHREAD_FLAGS)` to `dash_util_LDFLAGS` (Kittywhiskers Van Gogh)

Pull request description:

  ## Motivation

  Resolving a regression in Guix builds (see below)

  ```
    AR       libtest_util.a
  x86_64-linux-gnu-ld: dash_util-bitcoin-util.o: in function `std::thread::thread<void (&)(unsigned int, CBlockHeader&, unsigned int, unsigned int, std::atomic<bool>&), unsigned int&, std::reference_wrapper<CBlockHeader>, int&, int&, std::reference_wrapper<std::atomic<bool> >, void>(void (&)(unsigned int, CBlockHeader&, unsigned int, unsigned int, std::atomic<bool>&), unsigned int&, std::reference_wrapper<CBlockHeader>&&, int&, int&, std::reference_wrapper<std::atomic<bool> >&&)':
  /usr/include/c++/bits/std_thread.h:163:(.text._ZNSt6vectorISt6threadSaIS0_EE17_M_realloc_insertIJRFvjR12CBlockHeaderjjRSt6atomicIbEERjSt17reference_wrapperIS4_ERiSE_SC_IS7_EEEEvN9__gnu_cxx17__normal_iteratorIPS0_S2_EEDpOT_[_ZNSt6vectorISt6threadSaIS0_EE17_M_realloc_insertIJRFvjR12CBlockHeaderjjRSt6atomicIbEERjSt17reference_wrapperIS4_ERiSE_SC_IS7_EEEEvN9__gnu_cxx17__normal_iteratorIPS0_S2_EEDpOT_]+0x103): undefined reference to `pthread_create'
  x86_64-linux-gnu-ld: /usr/include/c++/bits/std_thread.h:163:(.text.startup+0x573): undefined reference to `pthread_create'
    CXXLD    test/test_dash
  x86_64-linux-gnu-ld: /gnu/store/dxk5rbssn95i797xzxycj1vzzmhw5r1b-gcc-cross-x86_64-linux-gnu-12.4.0-lib/lib/gcc/x86_64-linux-gnu/12.4.0/../../../../x86_64-linux-gnu/lib/../lib64/libstdc++.a(thread.o): in function `std::thread::_M_start_thread(std::unique_ptr<std::thread::_State, std::default_delete<std::thread::_State> >, void (*)())':
  (.text._ZNSt6thread15_M_start_threadESt10unique_ptrINS_6_StateESt14default_deleteIS1_EEPFvvE+0x28): undefined reference to `pthread_create'
  x86_64-linux-gnu-ld: /gnu/store/dxk5rbssn95i797xzxycj1vzzmhw5r1b-gcc-cross-x86_64-linux-gnu-12.4.0-lib/lib/gcc/x86_64-linux-gnu/12.4.0/../../../../x86_64-linux-gnu/lib/../lib64/libstdc++.a(thread.o): in function `std::thread::_M_start_thread(std::shared_ptr<std::thread::_Impl_base>, void (*)())':
  (.text._ZNSt6thread15_M_start_threadESt10shared_ptrINS_10_Impl_baseEEPFvvE+0x6f): undefined reference to `pthread_create'
  collect2: error: ld returned 1 exit status
  make[2]: *** [Makefile:8039: dash-util] Error 1
  make[2]: *** Waiting for unfinished jobs....
  make[2]: Leaving directory '/distsrc-base/distsrc-23.0.2-844-g6fbe514262c1-x86_64-linux-gnu/src'
  make[1]: *** [Makefile:21926: all-recursive] Error 1
  make[1]: Leaving directory '/distsrc-base/distsrc-23.0.2-844-g6fbe514262c1-x86_64-linux-gnu/src'
  make: *** [Makefile:804: all-recursive] Error 1
  ```

  ## Breaking Changes

  None expected.

  ## Checklist

  - [x] I have performed a self-review of my own code
  - [x] I have commented my code, particularly in hard-to-understand areas **(note: N/A)**
  - [x] I have added or updated relevant unit/integration/functional/e2e tests **(note: N/A)**
  - [x] I have made corresponding changes to the documentation **(note: N/A)**
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

ACKs for top commit:
  UdjinM6:
    ACK f8d5c00

Tree-SHA512: 391f5421593f063e1662d645cae5a82f71ab980b0ccd4a905b15f981bb0c9bcfef4cc9b1cb3f6b272c19e9b74129e92c0171734a1b622f256b0be5fcb49a115c

Author: PastaPastaPasta

src/Makefile.am

@@ -1130,7 +1130,7 @@ endif
 dash_util_SOURCES = bitcoin-util.cpp
 dash_util_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
 dash_util_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
-dash_util_LDFLAGS = $(LDFLAGS_WRAP_EXCEPTIONS) $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+dash_util_LDFLAGS = $(LDFLAGS_WRAP_EXCEPTIONS) $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS) $(PTHREAD_FLAGS)
 
 if TARGET_WINDOWS
 dash_util_SOURCES += bitcoin-util-res.rc