Slightly cleanup Wasm build recipes

There is no need to repeat the recipe for JS embedding for single-module
files; decoder is still special because it embeds two modules.

Makefile

@@ -179,19 +179,13 @@ js/meshopt_decoder.js: build/decoder_base.wasm build/decoder_simd.wasm tools/was
 	sed -i "s#\([\"']\).*\(;\s*//\s*embed! simd\)#\\1$$(cat build/decoder_simd.wasm | python3 tools/wasmpack.py)\\1\\2#" $@
 
 js/meshopt_encoder.js: build/encoder.wasm tools/wasmpack.py
-	sed -i "s#Built with clang.*#Built with $$($(WASMCC) --version | head -n 1 | sed 's/\s\+(.*//')#" $@
-	sed -i "s#Built from meshoptimizer .*#Built from meshoptimizer $$(cat src/meshoptimizer.h | grep -Po '(?<=version )[0-9.]+')#" $@
-	sed -i "s#\([\"']\).*\(;\s*//\s*embed! wasm\)#\\1$$(cat build/encoder.wasm | python3 tools/wasmpack.py)\\1\\2#" $@
-
 js/meshopt_simplifier.js: build/simplifier.wasm tools/wasmpack.py
-	sed -i "s#Built with clang.*#Built with $$($(WASMCC) --version | head -n 1 | sed 's/\s\+(.*//')#" $@
-	sed -i "s#Built from meshoptimizer .*#Built from meshoptimizer $$(cat src/meshoptimizer.h | grep -Po '(?<=version )[0-9.]+')#" $@
-	sed -i "s#\([\"']\).*\(;\s*//\s*embed! wasm\)#\\1$$(cat build/simplifier.wasm | python3 tools/wasmpack.py)\\1\\2#" $@
-
 js/meshopt_clusterizer.js: build/clusterizer.wasm tools/wasmpack.py
+
+js/meshopt_encoder.js js/meshopt_simplifier.js js/meshopt_clusterizer.js:
 	sed -i "s#Built with clang.*#Built with $$($(WASMCC) --version | head -n 1 | sed 's/\s\+(.*//')#" $@
 	sed -i "s#Built from meshoptimizer .*#Built from meshoptimizer $$(cat src/meshoptimizer.h | grep -Po '(?<=version )[0-9.]+')#" $@
-	sed -i "s#\([\"']\).*\(;\s*//\s*embed! wasm\)#\\1$$(cat build/clusterizer.wasm | python3 tools/wasmpack.py)\\1\\2#" $@
+	sed -i "s#\([\"']\).*\(;\s*//\s*embed! wasm\)#\\1$$(cat $< | python3 tools/wasmpack.py)\\1\\2#" $@
 
 js/%.module.js: js/%.js
 	sed '\#// export!#q' <$< >$@