Merge #13732: Depends: Fix Qt's rcc determinism

6b5506a286 Fix Qt's rcc determinism for depends/gitian (Fuzzbawls)

Pull request description:

  With the update to Qt 5.9 having been merged, Qt's `rcc` tool now embeds a file's last modified time in it's output. Since the build system generates temporary files for all locale translations (`*.qm` files) at build time, the resulting `qrc_bitcoin_locale.cpp` file was always being generated in a non-deterministic way.

  This is a backport of https://bugreports.qt.io/browse/QTBUG-62511, which is included in Qt versions 5.11+, that allows for an environment variable (`QT_RCC_SOURCE_DATE_OVERRIDE`) to override the behavior described above. This environment variable is in turn set in the gitian descriptors, as that is where determinism is vital for release purposes.

  Prior to this, the `qt_libbitcoinqt_a-qrc_bitcoin_locale.o` object file (included into `libbitcoinqt.a`) was returning a different `sha256sum` for each and every build, regardless of file contents change, thus breaking determinism in the resulting binaries.

  This should fix #13731

Tree-SHA512: 174017e41f9afc3950ef54a9419de81577ec900db9aec3c78ccd3d879c6aecaaeb944fde0615b933f43e6ca9d7898a27ec071cdd0b91cb772755a3012de96725

1 files changed, 15 insertions, 0 deletions

diff --git a/depends/patches/qt/fix_rcc_determinism.patch b/depends/patches/qt/fix_rcc_determinism.patch
new file mode 100644
index 0000000000..c1b07fe23a
--- /dev/null
+++ b/depends/patches/qt/fix_rcc_determinism.patch
@@ -0,0 +1,15 @@
+--- old/qtbase/src/tools/rcc/rcc.cpp
++++ new/qtbase/src/tools/rcc/rcc.cpp
+@@ -207,7 +207,11 @@ void RCCFileInfo::writeDataInfo(RCCResourceLibrary &lib)
+     if (lib.formatVersion() >= 2) {
+         // last modified time stamp
+         const QDateTime lastModified = m_fileInfo.lastModified();
+-        lib.writeNumber8(quint64(lastModified.isValid() ? lastModified.toMSecsSinceEpoch() : 0));
++        quint64 lastmod = quint64(lastModified.isValid() ? lastModified.toMSecsSinceEpoch() : 0);
++        static const quint64 sourceDate = 1000 * qgetenv("QT_RCC_SOURCE_DATE_OVERRIDE").toULongLong();
++        if (sourceDate != 0)
++            lastmod = sourceDate;
++        lib.writeNumber8(lastmod);
+         if (text || pass1)
+             lib.writeChar('\n');
+     }