Link with default rpath set to absolute path to LDC lib dir(s)

But still in a portable way for the portable prebuilt packages, which
will replace the absolute install path with `%%ldcbinarypath%/..` in the
config file, which will still lead to an absolute rpath in produced
binaries.

.circleci/config.yml

@@ -153,14 +153,10 @@ commonSteps: &commonSteps
         name: Hello world integration test with shared libs
         command: |
           cd ..
-          altLibSuffix="32"
-          if [ "$CI_OS" = "osx" ]; then
-            altLibSuffix=""
-          fi
           echo 'void main() { import std.stdio; writeln("Hello world, ", size_t.sizeof * 8, " bits"); }' > hello.d
-          $LDC_INSTALL_DIR/bin/ldc2 hello.d -m64 -of=hello64 -link-defaultlib-shared -L-Wl,-rpath,$LDC_INSTALL_DIR/lib
+          $LDC_INSTALL_DIR/bin/ldc2 hello.d -m64 -of=hello64 -link-defaultlib-shared
           ./hello64
-          $LDC_INSTALL_DIR/bin/ldc2 hello.d -m32 -of=hello32 -link-defaultlib-shared -L-Wl,-rpath,$LDC_INSTALL_DIR/lib$altLibSuffix
+          $LDC_INSTALL_DIR/bin/ldc2 hello.d -m32 -of=hello32 -link-defaultlib-shared
           ./hello32
     - run:
         name: Hello world integration test with LTO

ldc2_install.conf.in

@@ -7,7 +7,7 @@ default:
     // default switches injected before all explicit command-line switches
     switches = [
         "-I@INCLUDE_INSTALL_DIR@/ldc",
-        "-I@INCLUDE_INSTALL_DIR@",
+        "-I@INCLUDE_INSTALL_DIR@",@SHARED_LIBS_INSTALL_RPATH@
         "-defaultlib=phobos2-ldc,druntime-ldc"@ADDITIONAL_DEFAULT_LDC_SWITCHES@
     ];
     // default switches appended after all explicit command-line switches

runtime/CMakeLists.txt

@@ -252,12 +252,13 @@ if(MULTILIB AND NOT "${TARGET_SYSTEM}" MATCHES "APPLE")
 endif()
 
 # Set the -rpath linker option when shared runtime libraries are built.
-# The installed config file doesn't use SHARED_LIBS_RPATH.
 if(NOT ${BUILD_SHARED_LIBS} STREQUAL "OFF")
     if(MULTILIB AND NOT "${TARGET_SYSTEM}" MATCHES "APPLE")
-        set(SHARED_LIBS_RPATH "\n        \"-L-rpath\", \"-L${CMAKE_BINARY_DIR}/lib${LIB_SUFFIX}:${CMAKE_BINARY_DIR}/lib${MULTILIB_SUFFIX}\",")
+        set(SHARED_LIBS_RPATH         "\n        \"-L-rpath\", \"-L${CMAKE_BINARY_DIR}/lib${LIB_SUFFIX}:${CMAKE_BINARY_DIR}/lib${MULTILIB_SUFFIX}\",")
+        set(SHARED_LIBS_INSTALL_RPATH "\n        \"-L-rpath\", \"-L${CMAKE_INSTALL_LIBDIR}:${CMAKE_INSTALL_PREFIX}/lib${MULTILIB_SUFFIX}\",")
     else()
-        set(SHARED_LIBS_RPATH "\n        \"-L-rpath\", \"-L${CMAKE_BINARY_DIR}/lib${LIB_SUFFIX}\",")
+        set(SHARED_LIBS_RPATH         "\n        \"-L-rpath\", \"-L${CMAKE_BINARY_DIR}/lib${LIB_SUFFIX}\",")
+        set(SHARED_LIBS_INSTALL_RPATH "\n        \"-L-rpath\", \"-L${CMAKE_INSTALL_LIBDIR}\",")
     endif()
 endif()