Trim unnecessary -lrt and ws2_32 deps in the build.

The ws2_32 dependency comes from BIO, which is in libcrypto. Once it's
added there, it should get inherited by anything downstream, so we don't
need to keep listing it.

We also no longer need -lrt. We tried to remove it in
https://boringssl-review.googlesource.com/4622, but had to revert it in
https://boringssl-review.googlesource.com/4894 because of clock_gettime.

clock_gettime, per the Linux man page, is now in libc, not librt, as of
glibc 2.17. THat was released December 2012, well past our five year
watermark, so clean this part of the build up.

Change-Id: Ie6a07434b0cb02fe916b32ab8c326ec33d40bcb6
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/56606
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

crypto/CMakeLists.txt

@@ -330,7 +330,7 @@ if(FIPS_DELOCATE OR FIPS_SHARED)
   add_dependencies(crypto bcm_o_target)
 endif()
 
-SET_TARGET_PROPERTIES(crypto PROPERTIES LINKER_LANGUAGE C)
+set_target_properties(crypto PROPERTIES LINKER_LANGUAGE C)
 
 if(WIN32)
   target_link_libraries(crypto ws2_32)
@@ -436,7 +436,4 @@ add_executable(
 add_dependencies(crypto_test global_target)
 
 target_link_libraries(crypto_test test_support_lib boringssl_gtest crypto)
-if(WIN32)
-  target_link_libraries(crypto_test ws2_32)
-endif()
 add_dependencies(all_tests crypto_test)

decrepit/CMakeLists.txt

@@ -43,7 +43,4 @@ add_dependencies(decrepit_test global_target)
 
 target_link_libraries(decrepit_test test_support_lib boringssl_gtest decrepit
                       crypto)
-if(WIN32)
-  target_link_libraries(decrepit_test ws2_32)
-endif()
 add_dependencies(all_tests decrepit_test)

ssl/CMakeLists.txt

@@ -69,7 +69,4 @@ add_executable(
 add_dependencies(ssl_test global_target)
 
 target_link_libraries(ssl_test test_support_lib boringssl_gtest ssl crypto)
-if(WIN32)
-  target_link_libraries(ssl_test ws2_32)
-endif()
 add_dependencies(all_tests ssl_test)

tool/CMakeLists.txt

@@ -22,20 +22,5 @@ add_executable(
   transport_common.cc
 )
 install(TARGETS bssl DESTINATION ${CMAKE_INSTALL_BINDIR})
-
 add_dependencies(bssl global_target)
-
-if(WIN32)
-  target_link_libraries(bssl ws2_32)
-endif()
-
-if(APPLE OR WIN32 OR ANDROID)
-  target_link_libraries(bssl ssl crypto)
-else()
-  find_library(FOUND_LIBRT rt)
-  if(FOUND_LIBRT)
-    target_link_libraries(bssl ssl crypto -lrt)
-  else()
-    target_link_libraries(bssl ssl crypto)
-  endif()
-endif()
+target_link_libraries(bssl ssl crypto)

util/generate_build_files.py

@@ -550,7 +550,7 @@ R'''if(NOT ANDROID)
 endif()
 
 if(WIN32)
-  target_link_libraries(bssl ws2_32)
+  target_link_libraries(crypto ws2_32)
 endif()
 
 ''')