Merge #12788: [build] Tune wildcards for LIBSECP256K1 target

98b1813 [build] Tune wildcards for LIBSECP256K1 target (Karl-Johan Alm)

Pull request description:

  Automake would think the target was out of date every time because e.g. '.deps' was updated.

  Note: I am assuming that secp256k1 depends on `*.h`, `*.c`, ~~and `libsecp256k1-config.h`~~ (it's `.h` so already included), aside from pre-existing `include/*`. If there are other files that would require a rebuild of the `LIBSECP256K1` target, they should probably be added.

  It would be neat if you could exclude specific files, rather than split it up like this, but it doesn't seem possible (https://www.gnu.org/software/make/manual/html_node/Wildcard-Function.html#Wildcard-Function)

  Should probably note this:
  ```Bash
  $ V=1 make check VERBOSE=1
  Making check in src
  make[1]: Entering directory '/home/user/workspace/bitcoin/src'
  make[2]: Entering directory '/home/user/workspace/bitcoin/src'
  make  -C secp256k1 libsecp256k1.la
  make[3]: Entering directory '/home/user/workspace/bitcoin/src/secp256k1'
  make[3]: 'libsecp256k1.la' is up to date.
  make[3]: Leaving directory '/home/user/workspace/bitcoin/src/secp256k1'
  make  check-TESTS check-local
  make[3]: Entering directory '/home/user/workspace/bitcoin/src'
  make[4]: Entering directory '/home/user/workspace/bitcoin/src'
  make  -C secp256k1 libsecp256k1.la
  make[5]: Entering directory '/home/user/workspace/bitcoin/src/secp256k1'
  make[5]: 'libsecp256k1.la' is up to date.
  make[5]: Leaving directory '/home/user/workspace/bitcoin/src/secp256k1'
  PASS: test/test_bitcoin.exe
  ```

Tree-SHA512: 62b133c76e882788dae0c14208a9f5acdbd731c2e7a248f9e01f488b8ec13f9d637d7ad0d63e18d324bb4e088f1836a936649b0fb97bee679eaadedbeed5c981

Author: laanwj

src/Makefile.am

@@ -53,7 +53,7 @@ LIBBITCOIN_CRYPTO_AVX2 = crypto/libbitcoin_crypto_avx2.a
 LIBBITCOIN_CRYPTO += $(LIBBITCOIN_CRYPTO_AVX2)
 endif
 
-$(LIBSECP256K1): $(wildcard secp256k1/src/*) $(wildcard secp256k1/include/*)
+$(LIBSECP256K1): $(wildcard secp256k1/src/*.h) $(wildcard secp256k1/src/*.c) $(wildcard secp256k1/include/*)
 	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C $(@D) $(@F)
 
 # Make is not made aware of per-object dependencies to avoid limiting building parallelization