Adding support for msys.
diff --git a/tools/run_tests/sources_and_headers.json b/tools/run_tests/sources_and_headers.json
index 0b68315..b9a0044 100644
--- a/tools/run_tests/sources_and_headers.json
+++ b/tools/run_tests/sources_and_headers.json
@@ -5429,6 +5429,7 @@
"src/core/lib/support/string.c",
"src/core/lib/support/string.h",
"src/core/lib/support/string_posix.c",
+ "src/core/lib/support/string_util_win32.c",
"src/core/lib/support/string_win32.c",
"src/core/lib/support/string_win32.h",
"src/core/lib/support/subprocess_posix.c",
@@ -5447,6 +5448,7 @@
"src/core/lib/support/time_win32.c",
"src/core/lib/support/tls_pthread.c",
"src/core/lib/support/tmpfile.h",
+ "src/core/lib/support/tmpfile_msys.c",
"src/core/lib/support/tmpfile_posix.c",
"src/core/lib/support/tmpfile_win32.c",
"src/core/lib/support/wrap_memcpy.c"