--- a/src/cmarkgfm/build_cmark.py
+++ b/src/cmarkgfm/build_cmark.py
@@ -8,12 +8,8 @@
 import cffi
 
 
-# Get the directory for the cmark source files. It's under the package root
-# as /third_party/cmark/src
 HERE = os.path.dirname(os.path.abspath(__file__))
 PACKAGE_ROOT = os.path.abspath(os.path.join(HERE, '../../'))
-SRC_DIR = os.path.join(PACKAGE_ROOT, 'third_party/cmark/src')
-EXTENSIONS_SRC_DIR = os.path.join(PACKAGE_ROOT, 'third_party/cmark/extensions')
 UNIX_GENERATED_SRC_DIR = os.path.join(PACKAGE_ROOT, 'generated', 'unix')
 WIN_GENERATED_SRC_DIR = os.path.join(PACKAGE_ROOT, 'generated', 'windows')
 
@@ -27,20 +23,6 @@
     CMARK_MODULE_H = fh.read()
 
 
-def _get_sources(dir, exclude=set()):
-    sources = glob.iglob(os.path.join(dir, '*.c'))
-    return sorted([
-        os.path.relpath(path, start=PACKAGE_ROOT)
-        for path in
-        sources
-        if os.path.basename(path) not in exclude
-    ])
-
-
-SOURCES = _get_sources(SRC_DIR, exclude=set(['main.c']))
-SOURCES.extend(_get_sources(EXTENSIONS_SRC_DIR))
-
-
 def _compiler_type():
     """
     Gets the compiler type from distutils. On Windows with MSVC it will be
@@ -76,8 +58,8 @@
 ffibuilder.set_source(
     'cmarkgfm._cmark',
     CMARK_MODULE_H,
-    sources=SOURCES,
-    include_dirs=[SRC_DIR, EXTENSIONS_SRC_DIR, GENERATED_SRC_DIR],
+    include_dirs=[GENERATED_SRC_DIR],
+    libraries=["cmark-gfm", "cmark-gfm-extensions"],
     extra_compile_args=EXTRA_COMPILE_ARGS
 )