build: account for pure C sources in build-addons-napi

PR-URL: #21797
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: addaleax

Makefile

@@ -370,6 +370,7 @@ ADDONS_NAPI_BINDING_GYPS := \
 		$(wildcard test/addons-napi/*/binding.gyp))
 
 ADDONS_NAPI_BINDING_SOURCES := \
+	$(filter-out test/addons-napi/??_*/*.c, $(wildcard test/addons-napi/*/*.c)) \
 	$(filter-out test/addons-napi/??_*/*.cc, $(wildcard test/addons-napi/*/*.cc)) \
 	$(filter-out test/addons-napi/??_*/*.h, $(wildcard test/addons-napi/*/*.h))