Index: External/SPEC/CFP2000/CMakeLists.txt
===================================================================
--- External/SPEC/CFP2000/CMakeLists.txt
+++ External/SPEC/CFP2000/CMakeLists.txt
@@ -1,3 +1,4 @@
+list(APPEND LDFLAGS -lm)
 list(APPEND CPPFLAGS -DSPEC_CPU2000)
 if(CMAKE_SIZEOF_VOID_P EQUAL 8)
   list(APPEND CPPFLAGS -DSPEC_CPU2000_LP64)
Index: External/SPEC/CINT2000/176.gcc/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2000/176.gcc/CMakeLists.txt
+++ External/SPEC/CINT2000/176.gcc/CMakeLists.txt
@@ -4,6 +4,9 @@
 if(TARGET_OS STREQUAL "Darwin")
   list(APPEND LDFLAGS -Xlinker -stack_size -Xlinker 0x800000)
 endif()
+if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
+  list(APPEND CFLAGS -std=gnu89)
+endif()
 
 macro(test_input run_type ifile sfile)
   llvm_test_run(RUN_TYPE ${run_type}
Index: External/SPEC/CINT2000/252.eon/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2000/252.eon/CMakeLists.txt
+++ External/SPEC/CINT2000/252.eon/CMakeLists.txt
@@ -1,10 +1,14 @@
-list(APPEND CPPFLAGS -include errno.h -DHAS_ERRLIST -DUSE_STRERROR -DSPEC_STDCPP)
+list(APPEND CPPFLAGS -include errno.h -include string.h -DHAS_ERRLIST -DUSE_STRERROR -DSPEC_STDCPP)
 if(ARCH STREQUAL "PowerPC")
   list(APPEND CPPFLAGS -DFMAX_IS_DOUBLE)
 endif()
-list(APPEND CXXFLAGS -fno-exceptions -Wno-deprecated -fpermissive -stdlib=libstdc++)
-list(APPEND LDFLAGS -stdlib=libstdc++ -lm)
+list(APPEND CXXFLAGS -fno-exceptions -Wno-deprecated -fpermissive)
+list(APPEND LDFLAGS -lm)
 list(APPEND LIBS -lm)
+if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
+  list(APPEND CPPFLAGS -Wno-implicit-function-declaration)
+endif()
+
 include_directories(${BENCHMARK_DIR}/src)
 
 # There's more sourcefiles in the directory than necessary so enumerate the ones
Index: External/SPEC/CINT2000/253.perlbmk/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2000/253.perlbmk/CMakeLists.txt
+++ External/SPEC/CINT2000/253.perlbmk/CMakeLists.txt
@@ -31,6 +31,10 @@
   MD5.c
   md5c.c
 )
+
+list(APPEND CPPFLAGS -DSPEC_CPU2000_NEED_BOOL)
+list(APPEND LDFLAGS -lm)
+
 if(TARGET_OS STREQUAL "Win32")
   list(APPEND SourceNames nt_perlmain.c win32.c win32sck.c perllib.c)
   list(APPEND CPPFLAGS -DSPEC_CPU2000_NTOS -DWIN32 -D_CONSOLE)
@@ -40,6 +44,9 @@
   list(APPEND SourceNames unix_perlmain.c)
   list(APPEND CPPFLAGS -DSPEC_CPU2000_LINUX)
 endif()
+if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
+  list(APPEND CPPFLAGS -std=gnu89)
+endif()
 
 include(TestBigEndian)
 test_big_endian(IS_BIGENDIAN)
Index: External/SPEC/CINT2000/255.vortex/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2000/255.vortex/CMakeLists.txt
+++ External/SPEC/CINT2000/255.vortex/CMakeLists.txt
@@ -1,3 +1,5 @@
+list(APPEND LDFLAGS -lm)
+
 macro(test_input run_type input outfile)
   llvm_test_run(RUN_TYPE ${run_type}
     WORKDIR ${CMAKE_CURRENT_BINARY_DIR}/data/${run_type}/input
Index: External/SPEC/CINT2000/300.twolf/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2000/300.twolf/CMakeLists.txt
+++ External/SPEC/CINT2000/300.twolf/CMakeLists.txt
@@ -1,3 +1,4 @@
+list(APPEND CPPFLAGS -DHAVE_SIGNED_CHAR)
 list(APPEND LDFLAGS -lm)
 list(APPEND CFLAGS -Wno-return-type)
 
Index: External/SPEC/CINT2006/400.perlbench/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2006/400.perlbench/CMakeLists.txt
+++ External/SPEC/CINT2006/400.perlbench/CMakeLists.txt
@@ -1,5 +1,6 @@
 list(APPEND CPPFLAGS -DPERL_CORE -DI_TIME)
 list(APPEND CFLAGS -std=gnu89)
+list(APPEND LDFLAGS -lm)
 
 include_directories(${BENCHMARK_DIR}/src)
 
Index: External/SPEC/CINT2006/445.gobmk/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2006/445.gobmk/CMakeLists.txt
+++ External/SPEC/CINT2006/445.gobmk/CMakeLists.txt
@@ -1,4 +1,5 @@
 list(APPEND CPPFLAS -DWANT_STDC_PROTO)
+list(APPEND LDFLAGS -lm)
 
 set(Source "")
 foreach(dir IN ITEMS
Index: External/SPEC/CINT2006/456.hmmer/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2006/456.hmmer/CMakeLists.txt
+++ External/SPEC/CINT2006/456.hmmer/CMakeLists.txt
@@ -1,3 +1,5 @@
+list(APPEND LDFLAGS -lm)
+
 macro(test_input run_type input output)
   # The benchmark modifies the data file, need to copy a fresh one
   llvm_test_run(RUN_TYPE ${run_type} EXECUTABLE cp -f
Index: External/SPEC/CINT2006/464.h264ref/CMakeLists.txt
===================================================================
--- External/SPEC/CINT2006/464.h264ref/CMakeLists.txt
+++ External/SPEC/CINT2006/464.h264ref/CMakeLists.txt
@@ -1,6 +1,5 @@
-if(ARCH STREQUAL "PowerPC" AND TARGET_OS STREQUAL "Linux")
-  list(APPEND CFLAGS -fsigned-char)
-endif()
+list(APPEND LDFLAGS -lm)
+list(APPEND CFLAGS -fsigned-char)
 
 macro(test_input run_type leading level)
   llvm_test_run(RUN_TYPE ${run_type}