Dry run make is very useful for debugging. From the GNU make manual:
‘-n’ ‘--just-print’ ‘--dry-run’ ‘--recon’
“No-op”. Causes
maketo print the recipes that are needed to make the targets up to date, but not actually execute them. Note that some recipes are still executed, even with this flag (see How the MAKE Variable Works). Also any recipes needed to update included makefiles are still executed (see How Makefiles Are Remade).
On master (03689317021a72431762c1974530f2a980a7fffa) this option is not so useful:
$ make -n -C depends zlib
make: Entering directory '/home/hebasto/guix/GitHub/bitcoin/depends'
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps /home/hebasto/guix/GitHub/bitcoin/depends/sources
rm -f /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash
touch /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash
cd /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps; ( test -f /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz || ( ( mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 && echo Fetching zlib-1.2.11.tar.gz from https://www.zlib.net && curl --location --fail --connect-timeout 30 --retry 3 -o "/home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" "https://www.zlib.net/zlib-1.2.11.tar.gz" && echo "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1 /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" > /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && sha256sum -c /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && mv /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz && rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 ) || ( mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 && echo Fetching zlib-1.2.11.tar.gz from https://bitcoincore.org/depends-sources && curl --location --fail --connect-timeout 30 --retry 3 -o "/home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" "https://bitcoincore.org/depends-sources/zlib-1.2.11.tar.gz" && echo "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1 /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" > /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && sha256sum -c /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && mv /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz && rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 )))
cd /home/hebasto/guix/GitHub/bitcoin/depends/sources; sha256sum zlib-1.2.11.tar.gz >> /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash;
touch /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash
echo Extracting zlib...
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58; mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58 && echo "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1 /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz" > /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.zlib-1.2.11.tar.gz.hash && sha256sum -c /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.zlib-1.2.11.tar.gz.hash && tar --no-same-owner --strip-components=1 -xf /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.stamp_extracted
echo Preprocessing zlib...
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58 /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.patches-4416f3f0c58
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58;
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.stamp_preprocessed
echo Configuring zlib...
rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu; mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/lib; cd /home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu;
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.; PKG_CONFIG_LIBDIR=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/lib/pkgconfig PKG_CONFIG_PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/share/pkgconfig CMAKE_MODULE_PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/lib/cmake PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/native/bin:/home/hebasto/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin env CC="gcc -m64" CFLAGS="-pipe -O2 -I/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/include -fPIC" RANLIB="ranlib" AR="ar" ./configure --static --prefix=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu
/bin/sh: 1: cd: can't cd to /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/.
env: ‘./configure’: No such file or directory
make: *** [funcs.mk:268: /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-4416f3f0c58/./.stamp_configured] Error 127
With this PR:
$ make -n -C depends zlib
make: Entering directory '/home/hebasto/guix/GitHub/bitcoin/depends'
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps /home/hebasto/guix/GitHub/bitcoin/depends/sources
rm -f /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash
touch /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash
cd /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps; ( test -f /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz || ( ( mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 && echo Fetching zlib-1.2.11.tar.gz from https://www.zlib.net && curl --location --fail --connect-timeout 30 --retry 3 -o "/home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" "https://www.zlib.net/zlib-1.2.11.tar.gz" && echo "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1 /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" > /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && sha256sum -c /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && mv /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz && rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 ) || ( mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 && echo Fetching zlib-1.2.11.tar.gz from https://bitcoincore.org/depends-sources && curl --location --fail --connect-timeout 30 --retry 3 -o "/home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" "https://bitcoincore.org/depends-sources/zlib-1.2.11.tar.gz" && echo "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1 /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp" > /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && sha256sum -c /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/.zlib-1.2.11.tar.gz.hash && mv /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11/zlib-1.2.11.tar.gz.temp /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz && rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/work/download/zlib-1.2.11 )))
cd /home/hebasto/guix/GitHub/bitcoin/depends/sources; sha256sum zlib-1.2.11.tar.gz >> /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash;
touch /home/hebasto/guix/GitHub/bitcoin/depends/sources/download-stamps/.stamp_fetched-zlib-zlib-1.2.11.tar.gz.hash
echo Extracting zlib...
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a; mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a && echo "c3e5e9fdd5004dcb542feda5ee4f0ff0744628baf8ed2dd5d66f8ca1197cb1a1 /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz" > /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.zlib-1.2.11.tar.gz.hash && sha256sum -c /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.zlib-1.2.11.tar.gz.hash && tar --no-same-owner --strip-components=1 -xf /home/hebasto/guix/GitHub/bitcoin/depends/sources/zlib-1.2.11.tar.gz
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.stamp_extracted
echo Preprocessing zlib...
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.patches-38eb814ef0a
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a;
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.stamp_preprocessed
echo Configuring zlib...
rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu; mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/lib; cd /home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu;
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.; PKG_CONFIG_LIBDIR=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/lib/pkgconfig PKG_CONFIG_PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/share/pkgconfig CMAKE_MODULE_PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/lib/cmake PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/native/bin:/home/hebasto/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin env CC="gcc -m64" CFLAGS="-pipe -O2 -I/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/include -fPIC" RANLIB="ranlib" AR="ar" ./configure --static --prefix=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/./.stamp_configured
echo Building zlib...
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.; PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/native/bin:/home/hebasto/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin make libz.a
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/./.stamp_built
echo Staging zlib...
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a//home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.; PATH=/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/native/bin:/home/hebasto/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin make DESTDIR=/home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a install
rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/work/build/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/.stamp_staged
echo Postprocessing zlib...
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu;
touch /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu/.stamp_postprocessed
echo Caching zlib...
cd /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a//home/hebasto/guix/GitHub/bitcoin/depends/x86_64-pc-linux-gnu; find . | sort | tar --no-recursion -czf /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/zlib-1.2.11-38eb814ef0a.tar.gz -T -
mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/built/x86_64-pc-linux-gnu/zlib
rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/built/x86_64-pc-linux-gnu/zlib && mkdir -p /home/hebasto/guix/GitHub/bitcoin/depends/built/x86_64-pc-linux-gnu/zlib
mv /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a/zlib-1.2.11-38eb814ef0a.tar.gz /home/hebasto/guix/GitHub/bitcoin/depends/built/x86_64-pc-linux-gnu/zlib/zlib-1.2.11-38eb814ef0a.tar.gz
rm -rf /home/hebasto/guix/GitHub/bitcoin/depends/work/staging/x86_64-pc-linux-gnu/zlib/1.2.11-38eb814ef0a
cd /home/hebasto/guix/GitHub/bitcoin/depends/built/x86_64-pc-linux-gnu/zlib; sha256sum zlib-1.2.11-38eb814ef0a.tar.gz > /home/hebasto/guix/GitHub/bitcoin/depends/built/x86_64-pc-linux-gnu/zlib/zlib-1.2.11-38eb814ef0a.tar.gz.hash
make: Leaving directory '/home/hebasto/guix/GitHub/bitcoin/depends'