Install: log Rosetta detection, improve related docs

docs/install.md

@@ -115,7 +115,8 @@ and that it can be located using `pkg-config --modversion vips-cpp`.
 For help compiling libvips and its dependencies, please see
 [building libvips from source](https://www.libvips.org/install.html#building-libvips-from-source).
 
-The use of a globally-installed libvips is unsupported on Windows.
+The use of a globally-installed libvips is unsupported on Windows
+and on macOS when running Node.js under Rosetta.
 
 ## Building from source
 

install/libvips.js

@@ -128,9 +128,6 @@ try {
     if (arch === 'ia32' && !platformAndArch.startsWith('win32')) {
       throw new Error(`Intel Architecture 32-bit systems require manual installation of libvips >= ${minimumLibvipsVersion}`);
     }
-    if (platformAndArch === 'darwin-arm64') {
-      throw new Error("Please run 'brew install vips' to install libvips on Apple M1 (ARM64) systems");
-    }
     if (platformAndArch === 'freebsd-x64' || platformAndArch === 'openbsd-x64' || platformAndArch === 'sunos-x64') {
       throw new Error(`BSD/SunOS systems require manual installation of libvips >= ${minimumLibvipsVersion}`);
     }
@@ -153,7 +150,6 @@ try {
     if (!semverSatisfies(process.versions.node, supportedNodeVersion)) {
       handleError(new Error(`Expected Node.js version ${supportedNodeVersion} but found ${process.versions.node}`));
     }
-
     // Download to per-process temporary file
     const tarFilename = ['libvips', minimumLibvipsVersionLabelled, platformAndArch].join('-') + '.tar.br';
     const tarPathCache = path.join(libvips.cachePath(), tarFilename);

lib/libvips.js

@@ -115,6 +115,7 @@ const useGlobalLibvips = function () {
   }
   /* istanbul ignore next */
   if (isRosetta()) {
+    log('Detected Rosetta, skipping search for globally-installed libvips');
     return false;
   }
   const globalVipsVersion = globalLibvipsVersion();