Export 'SOURCE_DATE_EPOCH' in makefiles

Add configure check for 'export' (GNU make) or '.export' (BSD make)
makefile statements.

Remove no longer needed 'export' statements from workflows.

Signed-off-by: Christian Franke <christian.franke@t-online.de>

Author: chrfranke

.github/workflows/build-manually.yml

@@ -146,10 +146,10 @@ jobs:
           tar -xf "$distfile" &&
           version_sh=$("${distfile%.tar.gz}/src/getversion.sh" -s) && eval "${version_sh}" &&
           cd smartmontools-${SMARTMONTOOLS_PKG_VER} && mkdir build && cd build &&
-          export SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           ../configure --with-build-info='(GHA/clang/${{ github.event.inputs.suffix }})' \
             CC=clang CXX=clang++ \
-            ${{ github.event.inputs.cfg-options }} &&
+            ${{ github.event.inputs.cfg-options }} \
+            SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           ../src/clang-scan-build.sh \
             -f "../../smartmontools-ubuntu-x86_64-clang-report-${SMARTMONTOOLS_GIT_VER_FNAME}.tar.gz" \
             make ${{ github.event.inputs.make-options }} &&
@@ -191,10 +191,10 @@ jobs:
           tar -xf "$distfile" &&
           version_sh=$("${distfile%.tar.gz}/src/getversion.sh" -s) && eval "${version_sh}" &&
           cd smartmontools-${SMARTMONTOOLS_PKG_VER} && mkdir build && cd build &&
-          export SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           ../configure --with-build-info='(GHA/clang/${{ github.event.inputs.suffix }})' \
             CC=clang CXX=clang++ \
-            ${{ github.event.inputs.cfg-options }} &&
+            ${{ github.event.inputs.cfg-options }} \
+            SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           ../src/clang-scan-build.sh \
             -f "../../smartmontools-ubuntu-arm64-clang-report-${SMARTMONTOOLS_GIT_VER_FNAME}.tar.gz" \
             make ${{ github.event.inputs.make-options }} &&

.github/workflows/cygwin.yml

@@ -44,8 +44,8 @@ jobs:
       - name: Build with x86_64 gcc
         run: |
           mkdir build-gcc && cd build-gcc &&
-          export SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
-          ../configure --with-build-info='(GHA/Cygwin)' &&
+          ../configure --with-build-info='(GHA/Cygwin)' \
+            SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           make -j && make check &&
           make bin-dist bin_distfile="smartmontools-cygwin-x86_64-gcc-${SMARTMONTOOLS_GIT_VER_FNAME}.tar.gz"
         shell: bash --noprofile --norc -e -o igncr '{0}'
@@ -60,8 +60,8 @@ jobs:
       - name: Build with x86_64 clang
         run: |
           mkdir build-clang && cd build-clang &&
-          export SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
-          ../configure --with-build-info='(GHA/Cygwin)' CC=clang CXX=clang++ &&
+          ../configure --with-build-info='(GHA/Cygwin)' CC=clang CXX=clang++ \
+            SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           ../src/clang-scan-build.sh \
             -f "smartmontools-cygwin-clang-report-${SMARTMONTOOLS_GIT_VER_FNAME}.tar.gz" \
             make -j &&

.github/workflows/macos.yml

@@ -30,8 +30,9 @@ jobs:
       - name: Build (multiarch)
         run: |
           mkdir build && cd build &&
-          export SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
-          ../configure --with-build-info='(GHA/macOS)'  'CFLAGS=-arch arm64 -arch x86_64' 'CXXFLAGS=-arch arm64 -arch x86_64' &&
+          ../configure --with-build-info='(GHA/macOS)' \
+            CFLAGS=-'arch arm64 -arch x86_64' CXXFLAGS='-arch arm64 -arch x86_64' \
+            SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           make -j && make check &&
           make bin-dist bin_distfile="smartmontools-macos-${SMARTMONTOOLS_GIT_VER_FNAME}.tar.gz"
 

.github/workflows/msys2.yml

@@ -42,13 +42,11 @@ jobs:
           fetch-tags: true
 
       - name: Build (${{matrix.env}})
-        run: | # 'export SOURCE_DATE_EPOCH' suppresses an extra timestamp set by Clang LLD only
+        run: |
           version_sh=$(src/getversion.sh -s) && eval "${version_sh}" &&
           ./autogen.sh && mkdir build && cd build &&
-          SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           ../configure --with-build-info='(GHA/MSYS2)' --enable-static-link \
-            SOURCE_DATE_EPOCH=${SOURCE_DATE_EPOCH} &&
-          case ${{matrix.env}} in clang*) export SOURCE_DATE_EPOCH ;; esac &&
+            SOURCE_DATE_EPOCH=$((SMARTMONTOOLS_GIT_REV_EPOCH + 1)) &&
           make -j && make check &&
           make distinst_win32="smartmontools-mingw64-${{matrix.env}}-${SMARTMONTOOLS_GIT_VER_FNAME}.exe" \
             installer-win32

configure.ac

@@ -80,6 +80,7 @@ case "$host_os" in
 esac
 
 source_date_iso=
+dot_export="# export"
 if test -n "$SOURCE_DATE_EPOCH"; then
   # SOURCE_DATE_EPOCH must be either unset or numeric.
   test -z "`echo "$SOURCE_DATE_EPOCH" | sed -e 's,^$,X,' -e 's,[[0-9]],,g'`" \
@@ -97,9 +98,23 @@ if test -n "$SOURCE_DATE_EPOCH"; then
     cmd="unknown"
   done
   AC_MSG_RESULT([$cmd])
+
+  AC_MSG_CHECKING([how ${MAKE-make} exports environment variables])
+  dot_export=
+  #          GNU make BSD make
+  for exp in "export" ".export"; do
+    printf 'X=42\n%s X\nall:\n\ttest "$(X)" = "$$X"\n' "$exp" > conftest.make
+    if (unset X && ${MAKE-make} -f conftest.make >/dev/null 2>&1); then
+      dot_export=$exp; break
+    fi
+  done
+  rm -f conftest.make
+  AC_MSG_RESULT([${dot_export:-unknown}])
+  test -n "$dot_export" || dot_export="# unknown export"
 fi
 AC_SUBST([SOURCE_DATE_EPOCH])
 AC_SUBST([source_date_iso])
+AC_SUBST([dot_export])
 AM_CONDITIONAL(REPRODUCIBLE_BUILD, [test -n "$SOURCE_DATE_EPOCH"])
 
 # Checks for header files.
@@ -1161,6 +1176,14 @@ is not available.
 ]) ;;
 esac
 
+case $dot_export in
+  *unknown*) AC_MSG_WARN([
+This script was unable to determine how '${MAKE-make}' exports environment variables.
+Use 'export SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH' before running '${MAKE-make}'.
+Please inform $PACKAGE_BUGREPORT - Thanks!
+]) ;;
+esac
+
 case "$dist_tar:$SOURCE_DATE_EPOCH" in
   false:?*) AC_MSG_WARN([
 Reproducible tarballs require GNU tar which is not available.

lib/Makefile.am

@@ -4,8 +4,10 @@
 #
 
 if REPRODUCIBLE_BUILD
+@dot_export@ SOURCE_DATE_EPOCH
 if OS_DARWIN
-export ZERO_AR_DATE := 1
+ZERO_AR_DATE = 1
+@dot_export@ ZERO_AR_DATE
 endif
 endif
 

src/Makefile.am

@@ -4,9 +4,10 @@
 #
 
 if REPRODUCIBLE_BUILD
-set_source_date_epoch = SOURCE_DATE_EPOCH=$(SOURCE_DATE_EPOCH)
+@dot_export@ SOURCE_DATE_EPOCH
 if OS_DARWIN
-export ZERO_AR_DATE := 1
+ZERO_AR_DATE = 1
+@dot_export@ ZERO_AR_DATE
 endif
 endif
 
@@ -490,9 +491,9 @@ update-smart-drivedb.1m: update-smart-drivedb.8
 
 # Convert man pages into .html, .pdf and .txt
 MAN2HTML = man2html
-#MAN2HTML = $(set_source_date_epoch) groff -man -Thtml
-MAN2PDF = $(set_source_date_epoch) man -Tpdf -l
-#MAN2PDF = $(set_source_date_epoch) groff -man -Tpdf
+#MAN2HTML = groff -man -Thtml
+MAN2PDF = man -Tpdf -l
+#MAN2PDF = groff -man -Tpdf
 
 # Remove HTTP header and timestamp and fix links in man2html output
 FIXHTML = sed -e '1s,^Content-type.*,,' \