diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index d6c89e36009..fb89e417209 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -255,13 +255,13 @@ else
   AC_SUBST(LLVM_CROSS_COMPILING, [0])
 fi
 
-dnl Check to see if there's a "CVS" (or .svn) directory indicating that this
-dnl build is being done from a checkout. This sets up several defaults for the
-dnl command line switches. When we build with a CVS directory, we get a
-dnl debug with assertions turned on. Without, we assume a source release and we
-dnl get an optimized build without assertions. See --enable-optimized and
-dnl --enable-assertions below
-if test -d "CVS" -o -d "${srcdir}/CVS" -o -d ".svn" -o -d "${srcdir}/.svn"; then
+dnl Check to see if there's a "CVS" (or .svn or .git) directory indicating
+dnl that this build is being done from a checkout. This sets up several
+dnl defaults for the command line switches. When we build with a CVS directory,
+dnl we get a debug with assertions turned on. Without, we assume a source
+dnl release and we get an optimized build without assertions.
+dnl See --enable-optimized and --enable-assertions below
+if test -d "CVS" -o -d "${srcdir}/CVS" -o -d ".svn" -o -d "${srcdir}/.svn" -o -d ".git" -o -d "${srcdir}/.git"; then
   cvsbuild="yes"
   optimize="no"
   AC_SUBST(CVSBUILD,[[CVSBUILD=1]])