Merge #16141: build: remove GZIP export from gitian descriptors

bc8863b819 depends: remove usage of TAR_OPTIONS (fanquake)
3ff1f2a319 build: remove export GZIP from gitian descriptors (fanquake)

Pull request description:

  The `GZIP` environment variable is [deprecated](https://www.gnu.org/software/gzip/manual/gzip.html#Environment), and everywhere that we invoke `gzip` we are already passing `-9n` directly, i.e:
  ```base
    find bitcoin-* | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
  ```

  ```bash
  GZIP="-9n" gzip -h
  gzip: warning: GZIP environment variable is deprecated; use an alias or script
  Usage: gzip [OPTION]... [FILE]...
  ```

ACKs for commit bc8863:

Tree-SHA512: 2d5277f7bf096fd5bd0dda47dfaf2dc7a31cc5d91eb8cb42db9cbe060d07dff66bf8e1122a89a3a1b597a3b39dbf8d9a8da4f02e642f58e451ce9fb24cc59769

contrib/gitian-descriptors/gitian-linux.yml

@@ -50,8 +50,6 @@ script: |
 
   export QT_RCC_TEST=1
   export QT_RCC_SOURCE_DATE_OVERRIDE=1
-  export GZIP="-9n"
-  export TAR_OPTIONS="--mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME""
   export TZ="UTC"
   export BUILD_DIR=`pwd`
   mkdir -p ${WRAP_DIR}
@@ -150,8 +148,8 @@ script: |
   # Correct tar file order
   mkdir -p temp
   pushd temp
-  tar xf ../$SOURCEDIST
-  find bitcoin-* | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
+  tar -xf ../$SOURCEDIST
+  find bitcoin-* | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
   popd
 
   # Workaround for tarball not building with the bare tag version (prep)
@@ -184,8 +182,8 @@ script: |
     find ${DISTNAME}/bin -type f -executable -print0 | xargs -0 -n1 -I{} ../contrib/devtools/split-debug.sh {} {} {}.dbg
     find ${DISTNAME}/lib -type f -print0 | xargs -0 -n1 -I{} ../contrib/devtools/split-debug.sh {} {} {}.dbg
     cp ../doc/README.md ${DISTNAME}/
-    find ${DISTNAME} -not -name "*.dbg" | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}.tar.gz
-    find ${DISTNAME} -name "*.dbg" | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}-debug.tar.gz
+    find ${DISTNAME} -not -name "*.dbg" | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}.tar.gz
+    find ${DISTNAME} -name "*.dbg" | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}-debug.tar.gz
     cd ../../
     rm -rf distsrc-${i}
   done

contrib/gitian-descriptors/gitian-osx.yml

@@ -44,8 +44,6 @@ script: |
 
   export QT_RCC_TEST=1
   export QT_RCC_SOURCE_DATE_OVERRIDE=1
-  export GZIP="-9n"
-  export TAR_OPTIONS="--mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME""
   export TZ="UTC"
   export BUILD_DIR=`pwd`
   mkdir -p ${WRAP_DIR}
@@ -114,8 +112,8 @@ script: |
   # Correct tar file order
   mkdir -p temp
   pushd temp
-  tar xf ../$SOURCEDIST
-  find bitcoin-* | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
+  tar -xf ../$SOURCEDIST
+  find bitcoin-* | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
   popd
 
   # Workaround for tarball not building with the bare tag version (prep)
@@ -152,7 +150,7 @@ script: |
     cp ${BASEPREFIX}/${i}/native/bin/${i}-pagestuff unsigned-app-${i}/pagestuff
     mv dist unsigned-app-${i}
     pushd unsigned-app-${i}
-    find . | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-osx-unsigned.tar.gz
+    find . | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-osx-unsigned.tar.gz
     popd
 
     make deploy
@@ -162,7 +160,7 @@ script: |
     find . -name "lib*.la" -delete
     find . -name "lib*.a" -delete
     rm -rf ${DISTNAME}/lib/pkgconfig
-    find ${DISTNAME} | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}.tar.gz
+    find ${DISTNAME} | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}.tar.gz
     cd ../../
   done
   mkdir -p $OUTDIR/src

contrib/gitian-descriptors/gitian-win.yml

@@ -40,8 +40,6 @@ script: |
 
   export QT_RCC_TEST=1
   export QT_RCC_SOURCE_DATE_OVERRIDE=1
-  export GZIP="-9n"
-  export TAR_OPTIONS="--mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME""
   export TZ="UTC"
   export BUILD_DIR=`pwd`
   mkdir -p ${WRAP_DIR}
@@ -130,8 +128,8 @@ script: |
   # Correct tar file order
   mkdir -p temp
   pushd temp
-  tar xf ../$SOURCEDIST
-  find bitcoin-* | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
+  tar -xf ../$SOURCEDIST
+  find bitcoin-* | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ../$SOURCEDIST
   mkdir -p $OUTDIR/src
   cp ../$SOURCEDIST $OUTDIR/src
   popd
@@ -177,6 +175,6 @@ script: |
   cd $BUILD_DIR/windeploy
   mkdir unsigned
   cp $OUTDIR/bitcoin-*setup-unsigned.exe unsigned/
-  find . | sort | tar --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-win-unsigned.tar.gz
+  find . | sort | tar --mtime="$REFERENCE_DATE\\\ $REFERENCE_TIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-win-unsigned.tar.gz
   mv ${OUTDIR}/${DISTNAME}-x86_64-*-debug.zip ${OUTDIR}/${DISTNAME}-win64-debug.zip
   mv ${OUTDIR}/${DISTNAME}-x86_64-*.zip ${OUTDIR}/${DISTNAME}-win64.zip