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, 14 insertions, 34 deletions

diff --git a/indra/cmake/Python.cmake b/indra/cmake/Python.cmake
index a81c9307fc..ed595f6966 100644
--- a/indra/cmake/Python.cmake
+++ b/indra/cmake/Python.cmake
@@ -6,47 +6,27 @@ if (WINDOWS)
   # On Windows, explicitly avoid Cygwin Python.
 
   find_program(PYTHON_EXECUTABLE
-    NAMES python25.exe python23.exe python.exe
+    NAMES python.exe
     NO_DEFAULT_PATH # added so that cmake does not find cygwin python
     PATHS
-    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\2.7\\InstallPath]
-    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\2.6\\InstallPath]
-    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\2.5\\InstallPath]
-    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\2.4\\InstallPath]
-    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\2.3\\InstallPath]
-    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\2.7\\InstallPath]
-    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\2.6\\InstallPath]
-    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\2.5\\InstallPath]
-    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\2.4\\InstallPath]
-    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\2.3\\InstallPath]
-    )
-elseif (EXISTS /etc/debian_version)
-  # On Debian and Ubuntu, avoid Python 2.4 if possible.
-
-  find_program(PYTHON_EXECUTABLE python PATHS /usr/bin)
-
-  if (PYTHON_EXECUTABLE)
-    set(PYTHONINTERP_FOUND ON)
-  endif (PYTHON_EXECUTABLE)
-elseif (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
-  # On MAC OS X be sure to search standard locations first
-
-  string(REPLACE ":" ";" PATH_LIST "$ENV{PATH}")
-  find_program(PYTHON_EXECUTABLE
-    NAMES python python25 python24 python23
-    NO_DEFAULT_PATH # Avoid searching non-standard locations first
-    PATHS
-    /bin
-    /usr/bin
-    /usr/local/bin
-    ${PATH_LIST}
+    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\3.7\\InstallPath]
+    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\3.8\\InstallPath]
+    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\3.9\\InstallPath]
+    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\3.10\\InstallPath]
+    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\3.11\\InstallPath]
+    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\3.7\\InstallPath]
+    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\3.8\\InstallPath]
+    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\3.9\\InstallPath]
+    [HKEY_CURRENT_USER\\SOFTWARE\\Python\\PythonCore\\3.10\\InstallPath]
+    [HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\3.11\\InstallPath]
     )
+    include(FindPythonInterp)
+else()
+  find_program(PYTHON_EXECUTABLE python3)
 
   if (PYTHON_EXECUTABLE)
     set(PYTHONINTERP_FOUND ON)
   endif (PYTHON_EXECUTABLE)
-else (WINDOWS)
-  include(FindPythonInterp)
 endif (WINDOWS)
 
 if (NOT PYTHON_EXECUTABLE)