brew install fails on macOS M1

[maurotalevi]

brew install libsecp256k1
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Updated Formulae
Updated 1 formula.

==> Cloning https://github.com/bitcoin/secp256k1.git
Updating /Users/mauro/Library/Caches/Homebrew/libsecp256k1--git
origin/HEAD set to master
refs/remotes/origin/master
==> Checking out revision 98dac87839838b86094f1bccc71cc20e67b146cc
HEAD is now at 98dac87 Merge #858: Fix insecure links
HEAD is now at 98dac87 Merge #858: Fix insecure links
==> Installing libsecp256k1 from cuber/libsecp256k1
==> ./autogen.sh
==> ./configure --prefix=/opt/homebrew/Cellar/libsecp256k1/0.1 --enable-module-e
==> make install
Last 15 lines from /Users/mauro/Library/Logs/Homebrew/libsecp256k1/03.make:
CC src/bench_verify-bench_verify.o
CC src/bench_sign.o
CC src/bench_ecdh.o
CC src/bench_recover.o
CC src/exhaustive_tests-tests_exhaustive.o
gcc -Wall -Wextra -Wno-unused-function -g -O2 gen_context.o -o gen_context
./gen_context
CC src/libsecp256k1_la-secp256k1.lo
CC src/bench_internal-bench_internal.o
CC src/bench_ecmult-bench_ecmult.o
CC src/tests-tests.o
CCLD exhaustive_tests
clang: error: no such file or directory: '/usr/local/lib/libgmp.a'
make: *** [exhaustive_tests] Error 1
make: *** Waiting for unfinished jobs....

If reporting this issue please do so at (not Homebrew/brew or Homebrew/core):
https://github.com/cuber/homebrew-libsecp256k1/issues

[maurotalevi]

Problem is fixed by adding symlink:
$ ln -s /opt/homebrew/lib/libgmp.a /usr/local/lib/libgmp.a

On macOS M1 libs are installed in /opt/homebrew/lib