[External][SPEC2000] Add -Wl,-zmultidef linker option.

The SPEC CPU 2000 benchmarks 186.crafty and 300.twolf have symbols
defined in multiple source file. Add the -zmultidef option to the
linker for compatibility with older linkers.

Reviewed By: naromero77

Differential Revision: https://reviews.llvm.org/D95276
diff --git a/External/SPEC/CINT2000/186.crafty/CMakeLists.txt b/External/SPEC/CINT2000/186.crafty/CMakeLists.txt
index 1aad479..c1ff278 100644
--- a/External/SPEC/CINT2000/186.crafty/CMakeLists.txt
+++ b/External/SPEC/CINT2000/186.crafty/CMakeLists.txt
@@ -26,6 +26,8 @@
   list(APPEND CPPFLAGS -DHAS_LONGLONG)
 endif()
 
+list(APPEND LDFLAGS -Wl,-zmuldefs)
+
 set(SourceNames
   attacks.c
   boolean.c
diff --git a/External/SPEC/CINT2000/300.twolf/CMakeLists.txt b/External/SPEC/CINT2000/300.twolf/CMakeLists.txt
index 5c42eb3..82ad464 100644
--- a/External/SPEC/CINT2000/300.twolf/CMakeLists.txt
+++ b/External/SPEC/CINT2000/300.twolf/CMakeLists.txt
@@ -1,5 +1,6 @@
 list(APPEND CPPFLAGS -DHAVE_SIGNED_CHAR)
 list(APPEND LDFLAGS -lm)
+list(APPEND LDFLAGS -Wl,-zmuldefs)
 list(APPEND CFLAGS -Wno-return-type)
 
 macro(test_input run_type)