[build] Add "--with-prebuilt-webinterface" configure flag to force usage of prebuilt web UI

Author: chme

configure.ac

@@ -333,14 +333,31 @@ OWNTONE_ARG_DISABLE([include default web interface], [webinterface], [WEBINTERFA
 			[AS_IF([[test -f "$srcdir/web-src/htdocs/index.html"]],
 				[AM_MISSING_PROG([NPM], [[npm]])
 				AC_MSG_NOTICE([[
-npm not found, but a prebuilt web interface seems to be present.
-If you modify any web interface files, you will need to install it.
+npm not found, but a prebuilt web interface is present.
+If you modify any web interface source files, you will need to install npm.
 				]])],
 				[AC_MSG_ERROR([[npm required, please install it.]])])
 			]
 	)])
 AM_CONDITIONAL([COND_WEBINTERFACE], [[test "x$enable_webinterface" = "xyes"]])
 
+dnl Use prebuilt webinterface even if npm is available
+AC_ARG_WITH([prebuilt-webinterface],
+	[AS_HELP_STRING([--with-prebuilt-webinterface],
+		[Use prebuilt webinterface even if npm is available (default=no)]
+	)],
+	[AS_IF([[test -f "$srcdir/web-src/htdocs/index.html"]],
+		[[with_prebuilt_webinterface=yes]],
+		[AC_MSG_ERROR([[No prebuilt web interface found.]])]
+	)],
+	[[with_prebuilt_webinterface=]])
+if test "x$with_prebuilt_webinterface" = "xyes"; then
+    BUILD_WEBINTERFACE=
+else
+    BUILD_WEBINTERFACE=true
+fi
+AC_SUBST([BUILD_WEBINTERFACE])
+
 dnl Creating and defining users and groups
 OWNTONE_ARG_ENABLE([having 'make install' add user/group and 'make uninstall' delete], [install_user], [INSTALL_USER],
 	[AC_PATH_PROG([GETENT], [[getent]], [], [$PATH$PATH_SEPARATOR/usr/sbin])

web-src/Makefile.am

@@ -177,19 +177,19 @@ node_modules: $(PACKAGE_JSON)
 			cp "$$src_path" "$$dest_path"; \
 		done; \
 	fi
-	$(if $(NPM),$(NPM) clean-install)
+	$(if $(BUILD_WEBINTERFACE),$(NPM) clean-install)
 
 # Build the Vue.js application
 htdocs: node_modules $(WEB_FILES)
-	$(if $(NPM),$(NPM) run build)
+	$(if $(BUILD_WEBINTERFACE),$(NPM) run build)
 
 web: htdocs
 
 web-serve: node_modules
-	$(if $(NPM),$(NPM) run serve)
+	$(if $(BUILD_WEBINTERFACE),$(NPM) run serve)
 
 web-update:
-	$(if $(NPM),$(NPM) update)
+	$(if $(BUILD_WEBINTERFACE),$(NPM) update)
 
 web-check:
 	@echo "Verifying that all source files in 'src' and 'public' are listed in WEB_FILES ..."
@@ -208,10 +208,10 @@ web-check:
 	fi
 
 web-lint: node_modules
-	$(if $(NPM),$(NPM) run lint --no-fix)
+	$(if $(BUILD_WEBINTERFACE),$(NPM) run lint --no-fix)
 
 web-format: node_modules
-	$(if $(NPM),$(NPM) run format)
+	$(if $(BUILD_WEBINTERFACE),$(NPM) run format)
 
 all-local: htdocs