Update doc links contained within code

Throw rather than exit if require fails

.github/ISSUE_TEMPLATE/installation.md

@@ -13,6 +13,8 @@ Have you ensured the platform and version of Node.js used for `npm install` is t
 
 If you are installing as a `root` or `sudo` user, have you tried with the `npm install --unsafe-perm` flag?
 
+If you are using the `ignore-scripts` feature of `npm`, have you tried with the `npm install --ignore-scripts=false` flag?
+
 What is the complete output of running `npm install --verbose sharp`? Have you checked this output for useful error messages?
 
 What is the output of running `npx envinfo --binaries --languages --system --utilities`?

install/libvips.js

@@ -23,7 +23,7 @@ const fail = function (err) {
     npmLog.info('sharp', 'Are you trying to install as a root or sudo user? Try again with the --unsafe-perm flag');
   }
   npmLog.info('sharp', 'Attempting to build from source via node-gyp but this may fail due to the above error');
-  npmLog.info('sharp', 'Please see https://sharp.pixelplumbing.com/page/install for required dependencies');
+  npmLog.info('sharp', 'Please see https://sharp.pixelplumbing.com/install for required dependencies');
   process.exit(1);
 };
 

lib/constructor.js

@@ -16,15 +16,20 @@ try {
     help.push('- Ensure the version of Node.js used at install time matches that used at runtime');
   } else if (/invalid ELF header/.test(err.message)) {
     help.push(`- Ensure "${process.platform}" is used at install time as well as runtime`);
+  } else if (/Cannot find module/.test(err.message)) {
+    help.push('- Run "npm rebuild --verbose sharp" and look for errors');
   } else {
-    help.push('- Remove the "node_modules/sharp" directory, run "npm install" and look for errors');
+    help.push(
+      '- Remove the "node_modules/sharp" directory then run',
+      '  "npm install --ignore-scripts=false --verbose" and look for errors'
+    );
   }
   help.push(
-    '- Consult the installation documentation at https://sharp.pixelplumbing.com/en/stable/install/',
+    '- Consult the installation documentation at https://sharp.pixelplumbing.com/install',
     '- Search for this error at https://github.com/lovell/sharp/issues', ''
   );
-  console.error(help.join('\n'));
-  process.exit(1);
+  const error = help.join('\n');
+  throw new Error(error);
 }
 
 // Use NODE_DEBUG=sharp to enable libvips warnings

src/common.h

@@ -26,16 +26,16 @@
 // Verify platform and compiler compatibility
 
 #if (VIPS_MAJOR_VERSION < 8 || (VIPS_MAJOR_VERSION == 8 && VIPS_MINOR_VERSION < 9))
-#error libvips version 8.9.0+ is required - see sharp.pixelplumbing.com/page/install
+#error "libvips version 8.9.0+ is required - please see https://sharp.pixelplumbing.com/install"
 #endif
 
 #if ((!defined(__clang__)) && defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)))
-#error GCC version 4.6+ is required for C++11 features - see sharp.pixelplumbing.com/page/install#prerequisites
+#error "GCC version 4.6+ is required for C++11 features - please see https://sharp.pixelplumbing.com/install"
 #endif
 
 #if (defined(__clang__) && defined(__has_feature))
 #if (!__has_feature(cxx_range_for))
-#error clang version 3.0+ is required for C++11 features - see sharp.pixelplumbing.com/page/install#prerequisites
+#error "clang version 3.0+ is required for C++11 features - please see https://sharp.pixelplumbing.com/install"
 #endif
 #endif