Revert "Use `GNUInstallDirs` to support custom installation dirs. -- LLVM"

This reverts commit 6fd2db04d0f22ea22c5317d98ce2126aa64b6a73 since it
broke GreenDragon LLDB-Incremental bot:

https://green.lab.llvm.org/green/job/lldb-cmake/37560/console

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
GitOrigin-RevId: 797b50d4be873b4662983413a06806fca544c276
diff --git a/runtime/src/CMakeLists.txt b/runtime/src/CMakeLists.txt
index d0bd678..bdb867e 100644
--- a/runtime/src/CMakeLists.txt
+++ b/runtime/src/CMakeLists.txt
@@ -323,7 +323,7 @@
     install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E copy \"${LIBOMP_LIB_FILE}\"
       \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \${CMAKE_INSTALL_PREFIX}/bin)")
     install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E copy \"${LIBOMP_IMP_LIB_FILE}\"
-      \"${alias}${CMAKE_STATIC_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"\${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR}\")")
+      \"${alias}${CMAKE_STATIC_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR})")
   endforeach()
 else()
 
@@ -335,7 +335,7 @@
     foreach(alias IN LISTS LIBOMP_ALIASES)
       install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E create_symlink \"${LIBOMP_LIB_FILE}\"
         \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY
-        \"\$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR}\")")
+        \$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR})")
     endforeach()
   endif()
 endif()