message: Portability fix for the configure scripts generated
  Summary:
  Found thanks to the developer checks from the pkgsrc software
  distribution (for NetBSD, SmartOS, Minix, MacOS X, Linux, and more).
  This is a backport of secp256k1's PR511
  Test Plan:
  make check
  Reviewers: #bitcoin_abc, Fabien
diff: @@ -493,7 +493,7 @@ AM_CONDITIONAL([USE_ECMULT_STATIC_PRECOMPUTATION], [test x"$set_precomp" = x"yes
  AM_CONDITIONAL([ENABLE_MODULE_ECDH], [test x"$enable_module_ecdh" = x"yes"])
  AM_CONDITIONAL([ENABLE_MODULE_RECOVERY], [test x"$enable_module_recovery" = x"yes"])
  AM_CONDITIONAL([ENABLE_MODULE_SCHNORR], [test x"$enable_module_schnorr" = x"yes"])
  -AM_CONDITIONAL([USE_JNI], [test x"$use_jni" == x"yes"])
  +AM_CONDITIONAL([USE_JNI], [test x"$use_jni" = x"yes"])
  AM_CONDITIONAL([USE_EXTERNAL_ASM], [test x"$use_external_asm" = x"yes"])
  AM_CONDITIONAL([USE_ASM_ARM], [test x"$set_asm" = x"arm"])
  