diff --git a/config.m4 b/config.m4
index d2f2520..ca3f4f3 100644
--- a/config.m4
+++ b/config.m4
@@ -53,6 +53,7 @@
     src/core/lib/support/env_linux.cc \
     src/core/lib/support/env_posix.cc \
     src/core/lib/support/env_windows.cc \
+    src/core/lib/support/fork.cc \
     src/core/lib/support/histogram.cc \
     src/core/lib/support/host_port.cc \
     src/core/lib/support/log.cc \
@@ -118,6 +119,8 @@
     src/core/lib/iomgr/ev_windows.cc \
     src/core/lib/iomgr/exec_ctx.cc \
     src/core/lib/iomgr/executor.cc \
+    src/core/lib/iomgr/fork_posix.cc \
+    src/core/lib/iomgr/fork_windows.cc \
     src/core/lib/iomgr/gethostname_fallback.cc \
     src/core/lib/iomgr/gethostname_host_name_max.cc \
     src/core/lib/iomgr/gethostname_sysconf.cc \