Merge bitcoin/bitcoin#34604: guix: remove double export of TZ

62e378584e guix: don't export TZ twice (fanquake)
badcf1c68d guix: fix typo in guix-codesign (fanquake)

Pull request description:

  Remove a double export of `TZ` and fix a typo.

ACKs for top commit:
  janb84:
    ACK 62e378584e
  hebasto:
    ACK 62e378584e, I have reviewed the code and it looks OK.

Tree-SHA512: 6e0b66d20db2b0535bea7d29a28782d0ddd423eaace5f2aa708a227985d465e33def10e9f8ac5ea5482fe640ea0df4ca9df8e9f417bf5d040867564fc60aebd0

contrib/guix/guix-codesign

@@ -289,7 +289,7 @@ INFO: Codesigning ${VERSION:?not set} for platform triple ${HOST:?not set}:
 EOF
 
 
-        # Run the build script 'contrib/guix/libexec/build.sh' in the build
+        # Run the build script 'contrib/guix/libexec/codesign.sh' in the build
         # container specified by 'contrib/guix/manifest.scm'.
         #
         # Explanation of `guix shell` flags:

contrib/guix/libexec/build.sh

@@ -4,6 +4,9 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 export LC_ALL=C
 set -e -o pipefail
+
+# Environment variables for determinism
+export TAR_OPTIONS="--owner=0 --group=0 --numeric-owner --mtime='@${SOURCE_DATE_EPOCH}' --sort=name"
 export TZ=UTC
 
 # Although Guix _does_ set umask when building its own packages (in our case,
@@ -157,10 +160,6 @@ case "$HOST" in
         ;;
 esac
 
-# Environment variables for determinism
-export TAR_OPTIONS="--owner=0 --group=0 --numeric-owner --mtime='@${SOURCE_DATE_EPOCH}' --sort=name"
-export TZ="UTC"
-
 ####################
 # Depends Building #
 ####################