scons: minor touchups to plugin reporting

SConstruct

@@ -364,7 +364,7 @@ opts.AddVariables(
     
 # variables to pickle after successful configure step
 # these include all scons core variables as well as custom
-# env variables needed in Sconscript files
+# env variables needed in SConscript files
 pickle_store = [# Scons internal variables
         'CC', # compiler user to check if c deps compile during configure
         'CXX', # C++ compiler to compile mapnik
@@ -751,13 +751,13 @@ int main()
 """, '.cpp')
     # hack to avoid printed output
     context.Message('Checking for ICU version >= 4.2... ')
-    #context.did_show_result=1
+    context.did_show_result=1
     result = ret[1].strip()
     if not result:
         context.Result('error, could not get major and minor version from unicode/uversion.h')
         return False
     
-    color_print(4,'\nFound icu version... %s' % result)
+    color_print(4,'\nFound icu version... %s\n' % result)
     major, minor = map(int,result.split('.'))
     if major >= 4 and minor >= 2:
         return True
@@ -996,6 +996,7 @@ if not preconfigured:
     
     env['REQUESTED_PLUGINS'] = [ driver.strip() for driver in Split(env['INPUT_PLUGINS'])]
     
+    if len(env['REQUESTED_PLUGINS']):
         color_print(4,'Checking for requested plugins dependencies...')
         for plugin in env['REQUESTED_PLUGINS']:
             details = env['PLUGINS'][plugin]