SL-15742: Convert build scripts to Python 3

This changeset makes it possible to build the Second Life viewer using
Python 3. It is designed to be used with an equivalent Autobuild branch
so that a developer can compile without needing Python 2 on their
machine.

Breaking change: Python 2 support ending

Rather than supporting two versions of Python, including one that was
discontinued at the beginning of the year, this branch focuses on
pouring future effort into Python 3 only. As a result, scripts do not
need to be backwards compatible. This means that build environments,
be they on personal computers and on build agents, need to have a
compatible interpreter.

Notes

- SLVersionChecker will still use Python 2 on macOS
- Fixed the message template url used by template_verifier.py

1 files changed, 1 insertions, 0 deletions

diff --git a/indra/newview/llappviewer.cpp b/indra/newview/llappviewer.cpp
index 69606793db..d65cbbe3a5 100644
--- a/indra/newview/llappviewer.cpp
+++ b/indra/newview/llappviewer.cpp
@@ -1194,6 +1194,7 @@ bool LLAppViewer::init()
 	updater.executable = gDirUtilp->getExpandedFilename(LL_PATH_EXECUTABLE, updater_file);
 #elif LL_DARWIN
 	// explicitly run the system Python interpreter on SLVersionChecker.py
+	// Keep using python2 until SLVersionChecker is converted to python3.
 	updater.executable = "python";
 	updater_file = "SLVersionChecker.py";
 	updater.args.add(gDirUtilp->add(gDirUtilp->getAppRODataDir(), "updater", updater_file));