Makefile: only read NodeJS version when it is needed

Most make commands don't need to check for the NodeJS version, so only
do it when needed.

This avoids the following error on Windows for example when NodeJS is
not installed:

    /usr/bin/sh: line 1: node: command not found
    which: no node in (/c/Users/Ayke/bin:/clangarm64/bin:/usr/local/bin:/usr/bin:/usr/bin:/mingw64/bin:/usr/bin:/c/Users/Ayke/bin:/c/Users/Ayke/.vscode-server/cli/servers/Stable-e54c774e0add60467559eb0d1e229c6452cf8447/server/bin/remote-cli:/c/WINDOWS/system32:/c/WINDOWS:/c/WINDOWS/System32/Wbem:/c/WINDOWS/System32/WindowsPowerShell/v1.0:/c/WINDOWS/System32/OpenSSH:/cmd:/c/Users/Ayke/scoop/apps/mingw-mstorsjo-llvm-ucrt/current/bin:/c/Users/Ayke/scoop/apps/python/current/Scripts:/c/Users/Ayke/scoop/apps/python/current:/c/Users/Ayke/go/bin:/c/Users/Ayke/scoop/shims:/c/Users/Ayke/AppData/Local/Microsoft/WindowsApps:/usr/bin/vendor_perl:/usr/bin/core_perl)

Also, some users have been confused by the error message even though in
most cases it is harmless and can be ignored.

Author: aykevl

GNUmakefile

@@ -280,15 +280,15 @@ wasi-cm:
 	rsync -rv --delete --exclude go.mod --exclude '*_test.go' --exclude '*_json.go' --exclude '*.md' --exclude LICENSE $(shell go list -modfile ./internal/wasm-tools/go.mod -m -f {{.Dir}} $(WASM_TOOLS_MODULE)/cm)/ ./src/internal/cm
 
 # Check for Node.js used during WASM tests.
-NODEJS_VERSION := $(word 1,$(subst ., ,$(shell node -v | cut -c 2-)))
 MIN_NODEJS_VERSION=18
 
 .PHONY: check-nodejs-version
 check-nodejs-version:
-ifeq (, $(shell which node))
-	@echo "Install NodeJS version 18+ to run tests."; exit 1;
-endif
-	@if [ $(NODEJS_VERSION) -lt $(MIN_NODEJS_VERSION) ]; then echo "Install NodeJS version 18+ to run tests."; exit 1; fi
+	@# Check whether NodeJS is available.
+	@if ! command -v node 2>&1 >/dev/null; then echo "Install NodeJS version ${MIN_NODEJS_VERSION}+ to run tests."; exit 1; fi
+
+	@# Check whether the version is high enough.
+	@if [ "`node -v | sed 's/v\([0-9]\+\).*/\\1/g'`" -lt $(MIN_NODEJS_VERSION) ]; then echo "Install NodeJS version $(MIN_NODEJS_VERSION)+ to run tests."; exit 1; fi
 
 tinygo: ## Build the TinyGo compiler
 	@if [ ! -f "$(LLVM_BUILDDIR)/bin/llvm-config" ]; then echo "Fetch and build LLVM first by running:"; echo "  $(MAKE) llvm-source"; echo "  $(MAKE) $(LLVM_BUILDDIR)"; exit 1; fi