Add presets for source compat suite.

This should have been done some time ago, but it fell through the cracks. Ran
into some problems here, so I am taking care of it real quickly.

Author: gottesmm

utils/build-presets.ini

@@ -2221,3 +2221,92 @@ mixin-preset=stdlib_DA_standalone,build
 
 test
 validation-test
+
+#===----------------------------------------------------------------------===#
+# Preset for Source Compatibility Suite
+#===----------------------------------------------------------------------===#
+
+[preset: source_compat_suite_base]
+build-ninja
+llbuild
+swiftpm
+install-llbuild
+install-swift
+install-swiftpm
+reconfigure
+verbose-build
+skip-build-benchmarks
+
+install-destdir=%(install_destdir)s
+install-prefix=%(install_prefix)s
+installable-package=%(installable_package)s
+
+[preset: source_compat_suite_macos_base]
+mixin-preset=source_compat_suite_base
+build-subdir=compat_macos
+ios
+tvos
+watchos
+compiler-vendor=apple
+darwin-install-extract-symbols
+darwin-toolchain-alias=swift
+darwin-toolchain-bundle-identifier=org.swift.compat-macos
+darwin-toolchain-display-name-short=Swift Development Snapshot
+darwin-toolchain-display-name=Swift Development Snapshot
+darwin-toolchain-name=swift-DEVELOPMENT-SNAPSHOT
+darwin-toolchain-version=3.999.999
+llvm-install-components=libclang;libclang-headers;dsymutil
+swift-install-components=compiler;clang-builtin-headers;stdlib;sdk-overlay;license;sourcekit-xpc-service;swift-remote-mirror;swift-remote-mirror-headers
+symbols-package=%(symbols_package)s
+install-symroot=%(install_symroot)s
+
+[preset: source_compat_suite_linux_base]
+mixin-preset=source_compat_suite_base
+build-subdir=compat_linux
+foundation
+libdispatch
+xctest
+install-foundation
+install-libdispatch
+install-xctest
+swift-install-components=autolink-driver;compiler;clang-builtin-headers;stdlib;swift-remote-mirror;sdk-overlay;license
+
+[preset: source_compat_suite_macos_DA]
+mixin-preset=source_compat_suite_macos_base
+debug
+assertions
+
+[preset: source_compat_suite_macos_RA]
+mixin-preset=source_compat_suite_macos_base
+release
+assertions
+
+[preset: source_compat_suite_macos_R]
+mixin-preset=source_compat_suite_macos_base
+release
+no-assertions
+
+[preset: source_compat_suite_macos_D]
+mixin-preset=source_compat_suite_macos_base
+debug
+no-assertions
+
+[preset: source_compat_suite_linux_DA]
+mixin-preset=source_compat_suite_linux_base
+debug
+assertions
+
+[preset: source_compat_suite_linux_RA]
+mixin-preset=source_compat_suite_linux_base
+release
+assertions
+
+[preset: source_compat_suite_linux_R]
+mixin-preset=source_compat_suite_linux_base
+release
+no-assertions
+
+[preset: source_compat_suite_linux_D]
+mixin-preset=source_compat_suite_linux_base
+debug
+no-assertions