[compiler-rt] Don't require c++ headers when configuring compiler-rt builds

Summary:
A sysroot without c++ headers is able to build compiler-rt, don't
require them when configuring available architectures from cmake.

Reviewers: samsonov, beanz, compnerd

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D22469

llvm-svn: 276151
GitOrigin-RevId: ba2405cc5bb330659422afcc62a46cfd529fee78
diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index 824f5fc..64b78e1 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -92,8 +92,8 @@
 # platform. We use the results of these tests to build only the various target
 # runtime libraries supported by our current compilers cross-compiling
 # abilities.
-set(SIMPLE_SOURCE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/simple.cc)
-file(WRITE ${SIMPLE_SOURCE} "#include <stdlib.h>\n#include <limits>\nint main() {}\n")
+set(SIMPLE_SOURCE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/simple.c)
+file(WRITE ${SIMPLE_SOURCE} "#include <stdlib.h>\n#include <stdio.h>\nint main() { printf(\"hello, world\"); }\n")
 
 # Add $arch as supported with no additional flags.
 macro(add_default_target_arch arch)