pythongh-127146: Strip dash from Emscripten compiler version (python#128557)

`emcc -dumpversion` will sometimes say e.g., `4.0.0-git` but in this case
uname does not include `-git` in the version string. Use cut to delete
everything after the dash.

Author: hoodmane

configure

@@ -794,7 +794,7 @@ if test "$cross_compiling" = yes; then
 		_host_ident=$host_cpu
 		;;
 	*-*-emscripten)
-		_host_ident=$(emcc -dumpversion)-$host_cpu
+		_host_ident=$(emcc -dumpversion | cut -f1 -d-)-$host_cpu
 		;;
 	wasm32-*-* | wasm64-*-*)
 		_host_ident=$host_cpu