Fix standalone Windows build.

Don't link with dl, except on Linux where we have malloc tests.

Change-Id: I7b23acc854172e64628a55acecfaa9a661f74f77
Reviewed-on: https://boringssl-review.googlesource.com/2453
Reviewed-by: Adam Langley <agl@google.com>

ssl/test/CMakeLists.txt

@@ -10,4 +10,7 @@ add_executable(
 	test_config.cc
 )
 
-target_link_libraries(bssl_shim ssl crypto dl)
+target_link_libraries(bssl_shim ssl crypto)
+if (NOT APPLE AND NOT WIN32)
+	target_link_libraries(bssl_shim dl)
+endif()