update install.sh to build tor on macOS

install.sh

@@ -89,7 +89,9 @@ tor_deps_install ()
         'libssl-dev' \
         'zlib1g-dev' )
 
-    # TODO: darwin_deps
+    darwin_deps=( \
+        'libevent' \
+        'zlib' )
 
     if [[ ${use_os_deps_check} != '1' ]]; then
         return 0
@@ -97,8 +99,8 @@ tor_deps_install ()
         deb_deps_install "${debian_deps[@]}"
         return "$?"
     elif [[ ${install_os} == 'darwin' ]]; then
-        echo "FixMe: Darwin deps not specified. Trying to build."
-        return 0
+        dar_deps_install "${darwin_deps[@]}"
+        return "$?"
     else
         return 0
     fi
@@ -137,6 +139,7 @@ dar_deps_install ()
         return 1
     fi
 
+    if ! which virtualenv >/dev/null; then
         sudo_command=''
         if [ "$with_sudo" == 1 ]; then
             echo "
@@ -149,6 +152,7 @@ dar_deps_install ()
         if $with_jmvenv && ! $sudo_command pip3 install virtualenv; then
             return 1
         fi
+    fi
 }
 
 check_skip_build ()