[CMake] Fix RUNPATH of lib_InternalSwiftScan in Linux

libSwiftScan is built in 'lib' but installed in 'lib/swift/host' RUNPATH
should have correct '$ORIGIN/../{platform}' to load 'swiftCore' runtime
library.

(cherry picked from commit 4ccc866)
(cherry picked from commit 3badb3b)

Author: rintaro

tools/libSwiftScan/CMakeLists.txt

@@ -30,6 +30,19 @@ set_target_properties(libSwiftScan
     PROPERTIES
     OUTPUT_NAME ${SWIFT_SCAN_LIB_NAME})
 
+if(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD" AND BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
+  # Runtime INSTALL_RPATH are set by 'add_swift_host_library', but that expects
+  # libSwiftScan be installed in 'lib'. But since it's actually installed in 'lib/swift/host',
+  # we need to have correct runtime path to 'lib/swift/{platform}'.
+  # FIXME: BUILD_RPATH and INSTALL_PATH should be different
+  # FIXME: add_swift_host_library should accept 'DESTINATION' and handle installation
+  # FIXME: Build this library into 'lib/swift/host/' instead of 'lib/'
+  set_property(
+    TARGET libSwiftScan
+    APPEND PROPERTY INSTALL_RPATH "$ORIGIN/../${SWIFT_SDK_${SWIFT_HOST_VARIANT_SDK}_LIB_SUBDIR}"
+  )
+endif()
+
 if(SWIFT_SWIFT_PARSER)
   if(SWIFT_HOST_VARIANT_SDK IN_LIST SWIFT_DARWIN_PLATFORMS)
     # Ensure that we can find the host shared libraries.
@@ -39,7 +52,7 @@ if(SWIFT_SWIFT_PARSER)
     set_property(
       TARGET libSwiftScan
       APPEND PROPERTY INSTALL_RPATH "@loader_path/../host")
-  elseif(SWIFT_HOST_VARIANT_SDK STREQUAL "LINUX")
+  elseif(SWIFT_HOST_VARIANT_SDK MATCHES "LINUX|ANDROID|OPENBSD|FREEBSD")
     set_property(
       TARGET libSwiftScan
       APPEND PROPERTY INSTALL_RPATH "$ORIGIN/swift/host")