btfs: update build process

Closes #88.

Signed-off-by: Adrian Ho <215702+gromgit@users.noreply.github.com>

Formula/btfs-mac.rb

@@ -6,7 +6,8 @@ class BtfsMac < Formula
   url "https://github.com/johang/btfs/archive/refs/tags/v2.24.tar.gz"
   sha256 "d71ddefe3c572e05362542a0d9fd0240d8d4e1578ace55a8b3245176e7fd8935"
   license "GPL-3.0-only"
-  head "https://github.com/johang/btfs.git"
+  revision 1
+  head "https://github.com/johang/btfs.git", branch: "master"
 
   bottle do
     root_url "https://github.com/gromgit/homebrew-fuse/releases/download/btfs-mac-2.24"
@@ -19,21 +20,26 @@ class BtfsMac < Formula
 
   depends_on "autoconf" => :build
   depends_on "automake" => :build
-  depends_on "pkg-config" => :build
+  depends_on "pkgconf" => :build
   depends_on "libtorrent-rasterbar"
   depends_on MacfuseRequirement
   depends_on :macos
 
   def install
     setup_fuse
-    ENV.cxx11
-    inreplace "configure.ac", "fuse >= 2.8.0", "fuse >= 2.7.3"
     system "autoreconf", "--force", "--install", "--verbose"
     system "./configure", *std_configure_args, "--disable-silent-rules"
     system "make", "install"
   end
 
+  def caveats
+    <<~EOS
+      Mounting a torrent is fairly quick, but unmounting takes a long time.
+      Be patient.
+    EOS
+  end
+
   test do
-    system "#{bin}/btfs", "--help"
+    assert_match version.to_s, shell_output("#{bin}/btfs --version 2>&1")
   end
 end