From 0314f3ed8e6b0560fa67d2d6cf48133161334575 Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Sun, 1 May 2022 12:51:40 +0200
Subject: [PATCH] GNU testsuite: no need to rerun the GNU build

At least, two use cases:
* when hacking on test update
* when we want to rebuild only Rust coreutils with the right option

Indeed, the GNU code should not cache often in this case
---
 util/build-gnu.sh | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/util/build-gnu.sh b/util/build-gnu.sh
index 6f0ec32f7..83993fde9 100755
--- a/util/build-gnu.sh
+++ b/util/build-gnu.sh
@@ -62,14 +62,23 @@ for binary in $(./build-aux/gen-lists-of-programs.sh --list-progs); do
     }
 done
 
-./bootstrap
-./configure --quiet --disable-gcc-warnings
-#Add timeout to to protect against hangs
-sed -i 's|^"\$@|/usr/bin/timeout 600 "\$@|' build-aux/test-driver
-# Change the PATH in the Makefile to test the uutils coreutils instead of the GNU coreutils
-sed -i "s/^[[:blank:]]*PATH=.*/  PATH='${UU_BUILD_DIR//\//\\/}\$(PATH_SEPARATOR)'\"\$\$PATH\" \\\/" Makefile
-sed -i 's| tr | /usr/bin/tr |' tests/init.sh
-make -j "$(nproc)"
+if test -f gnu-built; then
+    echo "GNU build already found. Skip"
+    echo "'rm -f $(pwd)/gnu-built' to force the build"
+    echo "Note: the customization of the tests will still happen"
+    exit 0
+else
+    ./bootstrap
+    ./configure --quiet --disable-gcc-warnings
+    #Add timeout to to protect against hangs
+    sed -i 's|^"\$@|/usr/bin/timeout 600 "\$@|' build-aux/test-driver
+    # Change the PATH in the Makefile to test the uutils coreutils instead of the GNU coreutils
+    sed -i "s/^[[:blank:]]*PATH=.*/  PATH='${UU_BUILD_DIR//\//\\/}\$(PATH_SEPARATOR)'\"\$\$PATH\" \\\/" Makefile
+    sed -i 's| tr | /usr/bin/tr |' tests/init.sh
+    make -j "$(nproc)"
+    touch gnu-built
+fi
+
 # Handle generated factor tests
 t_first=00
 t_max=36