Update moxygen submodule to 15674097 (macOS gflags fix)

gmarzot · gmarzot · commit 73e7becab238 · 2026-03-10T13:49:27.000-04:00
Adds GFLAGS_SHARED OFF Linux-only fix: on macOS, glog is always
shared, so gflags must also be shared to avoid dual-linkage crashes.
diff --git a/deps/moxygen b/deps/moxygen
@@ -1 +1 @@
-Subproject commit 30bc5309ff1e31788f32e907a7b16059a72fee9b
+Subproject commit 156740973ceeaba3fc3ba5b39333025e2cfb8572
