Support LLVM_BUILD_LLVM_DYLIB

When built with `LLVM_BUILD_LLVM_DYLIB=On` LLVM will link all components
into a monolithic `libLLVM.so`, exported as the shared library target
`LLVM` in CMake.

Support this configuration of LLVM by looking for the
`LLVM_LINK_LLVM_DYLIB` variable exported by the LLVM CMake. Assume the
user has not limited the set of components linked into this DSO using
e.g. `LLVM_DYLIB_COMPONENTS`, in which case we may fail at static link
time.

Change-Id: I2d94349bb8af418c4938ccb76471f6e28f9836e5

Author: slinder1

amd/comgr/CMakeLists.txt

@@ -213,10 +213,14 @@ set(LLD_LIBS
   lldELF
   lldCommon)
 
-llvm_map_components_to_libnames(LLVM_LIBS
-  ${LLVM_TARGETS_TO_BUILD}
-  DebugInfoDWARF
-  Symbolize)
+if (LLVM_LINK_LLVM_DYLIB)
+  set(LLVM_LIBS LLVM)
+else()
+  llvm_map_components_to_libnames(LLVM_LIBS
+    ${LLVM_TARGETS_TO_BUILD}
+    DebugInfoDWARF
+    Symbolize)
+endif()
 
 target_link_libraries(amd_comgr
   PUBLIC