daemon: Bump to C++20 and use ‘std::format’ instead of ‘boost::format’.

* nix/boost: This directory and all files inside it are removed.
* nix/libstore/build.cc (Goal::trace): Use ‘std::string’ instead of ‘const format &’.
(DerivationGoal::startBuilder, ...): Use ‘std::format’ or ‘std::vformat’ instead of ‘boost::format’.
* nix/libstore/builtins.cc (builtinDownload): Same.
* nix/libstore/derivations.cc (DerivationOutput::parseHashInfo, ...): Same.
* nix/libstore/gc.cc (LocalStore::openGCLock, ...): Same.
* nix/libstore/globals.cc (Settings::_get): Same.
* nix/libstore/local-store.cc: (checkStoreNotSymlink, ...): Same.
* nix/libstore/misc.cc (dfsVisit, showBytes): Same
* nix/libstore/optimise-store.cc (makeWritable, ...): Same.
* nix/libstore/pathlocks.cc (openLockFile, ...): Same.
* nix/libstore/references.cc (search, scanForReferences): Same.
* nix/libstore/sqlite.hh (throwSQLiteError): Use ‘std::string’ instead of ‘const format &’.
* nix/libstore/sqlite.cc (throwSQLiteError): Use ‘std::string’ instead of ‘const format &’.
* nix/libstore/store-api.cc (assertStorePath, ...): Use ‘std::format’ instead of ‘boost::format’.
* nix/libutil/affinity.cc (setAffinityTo): Same.
* nix/libutil/archive.cc (dumpContents, ...): Same.
* nix/libutil/hash.cc (parseHash, parseHash32, parseHash16or32, hashFile): Same.
* nix/libutil/hash.hh (parseHash, parseHash32, parseHash16or32, isHash): Same.
* nix/libutil/serialise.cc : Add ‘<cassert>’ header file.
* nix/libutil/spawn.cc (addPhaseAfter, ...): Use ‘std::format’ instead of ‘boost::format’.
* nix/libutil/types.hh (FormatOrString): Removed.
(BaseError, BaseError::addPrefix, SysError, MakeError):
Use ‘std::string or std::string_view’ instead of ‘FormatOrString’.
* nix/libutil/util.hh (Nest::open, printMsg_, warnOnce, expect): Same.
* nix/libutil/util.cc (BaseError::BaseError, ...): Same.
(writeToStderr, _interrupted): Use std::uncaught_exceptions() instead of std::uncaught_exception()
* nix/nix-daemon/nix-daemon.cc (performOp, ...): Same.
* nix/nix-daemon/guix-daemon.cc (string_to_bool, ...): Same.
* nix/local.mk: Remove ‘libformat.a’ from ‘noinst_LIBRARIES’,
remove ‘libformat_a_SOURCES’ and ‘libformat_headers’,
remove ‘libformat_a_CPPFLAGS’ from ‘libutil_a_CPPFLAGS’ and ‘guix_daemon_LDADD’,
update ‘AM_CXXFLAGS’ to ‘-std=c++20’.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

nix/libstore/references.cc

@@ -5,7 +5,8 @@
 
 #include <map>
 #include <cstdlib>
-
+#include <cassert>
+#include <format>
 
 namespace nix {
 
@@ -37,8 +38,7 @@ static void search(const unsigned char * s, unsigned int len,
         if (!match) continue;
         string ref((const char *) s + i, refLength);
         if (hashes.find(ref) != hashes.end()) {
-            debug(format("found reference to `%1%' at offset `%2%'")
-                  % ref % i);
+            debug(std::format("found reference to `{}' at offset `{}'", ref, i));
             seen.insert(ref);
             hashes.erase(ref);
         }
@@ -93,7 +93,7 @@ PathSet scanForReferences(const string & path,
         string baseName = baseNameOf(i);
         string::size_type pos = baseName.find('-');
         if (pos == string::npos)
-            throw Error(format("bad reference `%1%'") % i);
+            throw Error(std::format("bad reference `{}'", i));
         string s = string(baseName, 0, pos);
         assert(s.size() == refLength);
         assert(backMap.find(s) == backMap.end());