[flang] Install runtime libs with LLVM_INSTALL_TOOLCHAIN_ONLY

[rovka]

Summary

Make sure that FortranDecimal, FortranRuntime and Fortran_main are
installed/packaged even when LLVM_INSTALL_TOOLCHAIN_ONLY is enabled.
They are used by flang to link executables, so they should be provided
even with minimal installs.

[awarzynski]

Makes sense, thanks for submitting this!

flang/cmake/modules/AddFlang.cmake

68–69

Hm, I'm not aware of there being "libflang" 🤔 .

flang/cmake/modules/AddFlang.cmake

 endmacro()
 
 macro(add_flang_subdirectory name)
   add_llvm_subdirectory(FLANG TOOL ${name})
 endmacro()
 
 macro(add_flang_library name)
   cmake_parse_arguments(ARG
-    "SHARED;STATIC"
+    "SHARED;STATIC;INSTALL_WITH_TOOLCHAIN"
     ""
     "ADDITIONAL_HEADERS"
     ${ARGN})
   set(srcs)
   if (MSVC_IDE OR XCODE)
     # Add public headers
     file(RELATIVE_PATH lib_path
       ${FLANG_SOURCE_DIR}/lib/
else()
     endif()
     set_property(GLOBAL APPEND PROPERTY FLANG_STATIC_LIBS ${name})
   endif()
 
   llvm_add_library(${name} ${LIBTYPE} ${ARG_UNPARSED_ARGUMENTS} ${srcs})
 
   if (TARGET ${name})
 
-    if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ${name} STREQUAL "libflang")
+    if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ${name} STREQUAL "libflang"
+        OR ARG_INSTALL_WITH_TOOLCHAIN)
       get_target_export_arg(${name} Flang export_to_flangtargets UMBRELLA flang-libraries)
       install(TARGETS ${name}
         COMPONENT ${name}
         ${export_to_flangtargets}
         LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
         ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
         RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 

flang/lib/Decimal/CMakeLists.txt

 
-add_flang_library(FortranDecimal
+add_flang_library(FortranDecimal INSTALL_WITH_TOOLCHAIN
   binary-to-decimal.cpp
   decimal-to-binary.cpp
 )

flang/runtime/CMakeLists.txt

add_flang_library(FortranRuntime
   type-code.cpp
   type-info.cpp
   unit.cpp
   unit-map.cpp
   utf.cpp
 
   LINK_LIBS
   FortranDecimal
+
+  INSTALL_WITH_TOOLCHAIN
 )

flang/runtime/FortranMain/CMakeLists.txt

-add_flang_library(Fortran_main STATIC
+add_flang_library(Fortran_main STATIC INSTALL_WITH_TOOLCHAIN
   Fortran_main.c
 )