diff --git a/HISTORY.rst b/HISTORY.rst
index 0f5843c4..5b4f13df 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -13,8 +13,10 @@ PlatformIO 3.0
 * Handle dynamic ``SRC_FILTER`` environment variable from
   `library.json extra script <http://docs.platformio.org/page/librarymanager/config.html#extrascript>`__
 * Improved auto-detecting of mbed-enabled media disks
-* Update Git-submodules for development platforms and libraries which were
-  installed from repository
+* Automatically update Git-submodules for development platforms and libraries
+  that were installed from repository
+* Add support for ``.*cc`` extension
+  (`issue #939 <https://github.com/platformio/platformio-core/issues/939>`_)
 
 -------
 
diff --git a/platformio/builder/tools/piolib.py b/platformio/builder/tools/piolib.py
index 0531d65e..1daedc6b 100644
--- a/platformio/builder/tools/piolib.py
+++ b/platformio/builder/tools/piolib.py
@@ -65,7 +65,8 @@ class LibBuilderFactory(object):
         # check source files
         for root, _, files in os.walk(path, followlinks=True):
             for fname in files:
-                if not env.IsFileWithExt(fname, ("c", "cpp", "h", "hpp")):
+                if not env.IsFileWithExt(
+                        fname, piotool.SRC_BUILD_EXT + piotool.SRC_HEADER_EXT):
                     continue
                 with open(join(root, fname)) as f:
                     content = f.read()
diff --git a/platformio/builder/tools/platformio.py b/platformio/builder/tools/platformio.py
index 8b09e248..1f2186cf 100644
--- a/platformio/builder/tools/platformio.py
+++ b/platformio/builder/tools/platformio.py
@@ -27,7 +27,7 @@ from SCons.Util import case_sensitive_suffixes, is_Sequence
 
 from platformio.util import glob_escape, pioversion_to_intstr
 
-SRC_BUILD_EXT = ["c", "cpp", "S", "spp", "SPP", "sx", "s", "asm", "ASM"]
+SRC_BUILD_EXT = ["c", "cc", "cpp", "S", "spp", "SPP", "sx", "s", "asm", "ASM"]
 SRC_HEADER_EXT = ["h", "hpp"]
 SRC_FILTER_DEFAULT = ["+<*>", "-<.git%s>" % sep, "-<svn%s>" % sep]