[gn build] Manually port b4e39e4

Author: aeubanks

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -223,6 +223,7 @@ write_cmake_config("config") {
       "HAVE_SIGALTSTACK=",
       "HAVE_STRERROR_R=",
       "HAVE_SYSCONF=",
+      "HAVE_SYS_IOCTL_H=",
       "HAVE_SYS_MMAN_H=",
       "HAVE_UNISTD_H=",
       "HAVE__CHSIZE_S=1",
@@ -250,6 +251,7 @@ write_cmake_config("config") {
       "HAVE_SIGALTSTACK=1",
       "HAVE_STRERROR_R=1",
       "HAVE_SYSCONF=1",
+      "HAVE_SYS_IOCTL_H=1",
       "HAVE_SYS_MMAN_H=1",
       "HAVE_UNISTD_H=1",
       "HAVE__CHSIZE_S=",