libgit2: unbundle pcre (#85049)

libgit2 has bundled pcre (not pcre2) in
https://github.com/libgit2/libgit2/pull/4935

Before this change configure printed "regex, using bundled PCRE",
after this change it prints "regex, using system PCRE".

pkgs/development/libraries/git2/default.nix

@@ -1,5 +1,5 @@
 { stdenv, fetchFromGitHub, cmake, pkgconfig, python3
-, zlib, libssh2, openssl, http-parser
+, zlib, libssh2, openssl, pcre, http-parser
 , libiconv, Security
 }:
 
@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ cmake python3 pkgconfig ];
 
-  buildInputs = [ zlib libssh2 openssl http-parser ]
+  buildInputs = [ zlib libssh2 openssl pcre http-parser ]
     ++ stdenv.lib.optional stdenv.isDarwin Security;
 
   propagatedBuildInputs = stdenv.lib.optional (!stdenv.isLinux) libiconv;