Merge bitcoin/bitcoin#29689: lint: scripted-diff verification also requires GNU grep

3bf4f8d lint: scripted-diff verification also requires GNU grep (Sjors Provoost)

Pull request description:

  I noticed while trying to verify all historical `scripted-diff:` commits on macOS that some scripts require GNU sed.

  For example 0d6d2b6 uses `git grep --perl-regexp`.

ACKs for top commit:
  hernanmarino:
    cr ACK 3bf4f8d
  maflcko:
    utACK 3bf4f8d
  achow101:
    ACK 3bf4f8d
  alfonsoromanz:
    Tested ACK 3bf4f8d
  kristapsk:
    cr utACK 3bf4f8d

Tree-SHA512: 09a060ab1bafad03df60d0f20c3dd1451850868dbd66ea38b18178b6230c1f06cf48622db82d9c51422d5689962ee0cd7aae0a31f84bd6d878215e6d73c1d47e

Author: achow101

test/lint/commit-script-check.sh

@@ -22,6 +22,11 @@ if ! sed --help 2>&1 | grep -q 'GNU'; then
     exit 1;
 fi
 
+if ! grep --help 2>&1 | grep -q 'GNU'; then
+    echo "Error: the installed grep package is not compatible. Please make sure you have GNU grep installed in your system.";
+    exit 1;
+fi
+
 RET=0
 PREV_BRANCH=$(git name-rev --name-only HEAD)
 PREV_HEAD=$(git rev-parse HEAD)