build: install the executable targets

This is the first and last step towards enabling swift-driver on
Windows.  The current swift-driver test suite passes on Windows, and
with the changes now merged, `swift build --use-integrated-swift-driver`
works.  This change will extract the tools so that we can package them
up.  This sets the stage for the last change needed in SPM and allows
experimenting with packaging now.

Author: compnerd

Sources/swift-build-sdk-interfaces/CMakeLists.txt

@@ -11,3 +11,6 @@ add_executable(swift-build-sdk-interfaces
 target_link_libraries(swift-build-sdk-interfaces PUBLIC
   SwiftDriver
   SwiftDriverExecution)
+
+install(TARGETS swift-build-sdk-interfaces
+  DESTINATION bin)

Sources/swift-driver/CMakeLists.txt

@@ -10,4 +10,7 @@ add_executable(swift-driver
   main.swift)
 target_link_libraries(swift-driver PUBLIC
   SwiftDriver
-  SwiftDriverExecution)
+  SwiftDriverExecution)
+
+install(TARGETS swift-driver
+  DESTINATION bin)

Sources/swift-help/CMakeLists.txt

@@ -11,4 +11,7 @@ add_executable(swift-help
 target_link_libraries(swift-help PUBLIC
   SwiftOptions
   ArgumentParser
-  TSCBasic)
+  TSCBasic)
+
+install(TARGETS swift-help
+  DESTINATION bin)