php-imap: PHP 7.4 compatability w/ environment patching

Author: crishoj

Formula/php-imap.rb

@@ -13,4 +13,12 @@ class PhpImap < PhpExtensionFormula
     --with-imap-ssl=#{Formula["[email protected]"].opt_prefix}
     --with-kerberos
   ]
+
+  def install
+    ENV["PHP_OPENSSL"] = "yes"
+    # system pkg-config missing
+    ENV["KERBEROS_CFLAGS"] = " "
+    ENV["KERBEROS_LIBS"] = "-lkrb5"
+    super
+  end
 end