Replace autobuild with vcpkg and CMake build system modernization

.github/dependabot.yaml

@@ -5,3 +5,8 @@ updates:
     directory: /
     schedule:
       interval: monthly
+
+  - package-ecosystem: vcpkg
+    directory: /indra # The location of vcpkg.json
+    schedule:
+      interval: weekly

.gitignore

@@ -1,9 +1,7 @@
 # By extension
 *.DS_Store
 *.bak
-*.diff
 *.orig
-*.patch
 *.pyc
 *.rej
 *.swp
@@ -17,23 +15,22 @@
 *~
 
 # Specific paths and/or names
+.vs
 .venv
+.cache
+.zed
 CMakeCache.txt
 cmake_install.cmake
 LICENSES
-build-*
+build*
 debian/files
 debian/secondlife-appearance-utility*
 debian/secondlife-viewer*
 indra/.distcc
 indra/out/*
 
 indra/packages/*
-build-vc80/
-build-vc100/
-build-vc120/
-build-vc*-32/
-build-vc*-64/
+build-*/
 indra/CMakeFiles
 indra/build-vc[0-9]*
 indra/lib/mono/1.0/*.dll
@@ -91,3 +88,5 @@ web/secondlife.com.*
 
 .env
 .vscode
+.vs
+.zed

README.md

@@ -26,11 +26,33 @@ Third party maintained forks, which include Linux compatible builds, are indexed
 
 ## Build Instructions
 
-[Windows](https://wiki.secondlife.com/wiki/Build_the_Viewer_on_Windows)
+The Second Life viewer uses CMake for build system generation and vcpkg for dependency management. 
 
-[Mac](https://wiki.secondlife.com/wiki/Build_the_Viewer_on_macOS)
+### Platform-specific setup guides
 
-[Linux](https://wiki.secondlife.com/wiki/Build_the_Viewer_on_Linux)
+[Windows](doc/BUILD.WINDOWS.md)
+
+[Mac](doc/BUILD.MAC.md)
+
+[Linux](doc/BUILD.LINUX.md)
+
+### Configuration Types
+| CMake                      | Description                                                                         |
+|:---------------------------|:------------------------------------------------------------------------------------|
+| Debug                      | A debug build linked against debug libraries                                        |
+| OptDebug                   | A debug build linked with release libraries                                         |
+| RelWithDebInfo             | A release optimized build with asserts linked with release libraries                |
+| Release                    | A release optimized build linked with release libraries                             |
+
+### Build Options
+
+| CMake                      | Description                                                                         | Default |
+|:---------------------------|:------------------------------------------------------------------------------------|---------|
+| BUILD_VIEWER               | Build viewer binaries                                                               | ON      |
+| BUILD_APPEARANCE_UTIL      | Build appearance utility                                                            | OFF     |
+| BUILD_TESTING              | Build test binries.                                                                 | OFF     |
+| PACKAGE                    | Build installer packages when viewer build enabled                                  | ON      |
+| USE_OPENAL                 | Build with support for the OpenAL audio engine                                      | ON      |
 
 ## Contribute