This is how you can lock meson build dependencies. Not sure why I didn't think of this before but you just put the .wrap files somewhere and instead of meson wrap install you copy them into subprojects.

wraps/efsw.wrap

@@ -0,0 +1,11 @@
+[wrap-git]
+url = https://github.com/SpartanJ/efsw.git
+revision = 1.3.1
+depth = 1
+method = cmake
+# patch_filename =
+# patch_hash =
+
+
+[provide]
+efsw = efsw_dep