diff --git a/platformio/builder/main.py b/platformio/builder/main.py
index 9c8ad03b..3ae92943 100644
--- a/platformio/builder/main.py
+++ b/platformio/builder/main.py
@@ -75,7 +75,7 @@ MULTILINE_VARS = [
 
 DEFAULT_ENV_OPTIONS = dict(
     tools=[
-        "ar", "as", "gcc", "g++", "gnulink", "platformio", "pioplatform",
+        "ar", "gas", "gcc", "g++", "gnulink", "platformio", "pioplatform",
         "piowinhooks", "piolib", "pioupload", "piomisc", "pioide"
     ],  # yapf: disable
     toolpath=[join(util.get_source_dir(), "builder", "tools")],
diff --git a/platformio/builder/tools/piolib.py b/platformio/builder/tools/piolib.py
index 9c17daec..bc08f4f1 100644
--- a/platformio/builder/tools/piolib.py
+++ b/platformio/builder/tools/piolib.py
@@ -796,9 +796,8 @@ def GetLibBuilders(env):  # pylint: disable=too-many-branches
 
 
 def BuildProjectLibraries(env):
-    lib_builders = env.GetLibBuilders()
 
-    def correct_found_libs():
+    def correct_found_libs(lib_builders):
         # build full dependency graph
         found_lbs = [lb for lb in lib_builders if lb.dependent]
         for lb in lib_builders:
@@ -836,13 +835,15 @@ def BuildProjectLibraries(env):
     print "Library Dependency Finder -> http://bit.ly/configure-pio-ldf"
     print "Modes: Finder/%s Compatibility/%s" % (ldf_mode,
                                                  project.lib_compat_mode)
+
+    lib_builders = env.GetLibBuilders()
     print "Collected %d compatible libraries" % len(lib_builders)
 
     print "Scanning dependencies..."
     project.search_deps_recursive()
 
     if ldf_mode.startswith("chain") and project.depbuilders:
-        correct_found_libs()
+        correct_found_libs(lib_builders)
 
     if project.depbuilders:
         print "Dependency Graph"
diff --git a/platformio/builder/tools/platformio.py b/platformio/builder/tools/platformio.py
index a02a6fe9..4becee3e 100644
--- a/platformio/builder/tools/platformio.py
+++ b/platformio/builder/tools/platformio.py
@@ -44,7 +44,7 @@ def BuildProgram(env):
 
     env.PrintSystemInfo()
 
-    # fix ASM handling under non-casitive OS
+    # fix ASM handling under non case-sensitive OS
     if not case_sensitive_suffixes(".s", ".S"):
         env.Replace(AS="$CC", ASCOM="$ASPPCOM")