diff --git a/Makefile.am b/Makefile.am
index 26704345..03f42c07 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 ACLOCAL_AMFLAGS = -I m4
 SUBDIRS = contrib src m4 .
 EXTRA_DIST = acinclude.m4 libmicrohttpd.pc.in libmicrospdy.pc.in  \
diff --git a/contrib/Makefile.am b/contrib/Makefile.am
index 58f2c320..a5f99e14 100644
--- a/contrib/Makefile.am
+++ b/contrib/Makefile.am
@@ -1 +1,2 @@
+# This Makefile.am is in the public domain
 EXTRA_DIST = xcc ascebc mhd.png mhd.svg mhd_logo.png
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 14b1f1e0..287514dc 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 man_MANS = libmicrohttpd.3
 
 SUBDIRS = . examples doxygen
diff --git a/doc/doxygen/Makefile.am b/doc/doxygen/Makefile.am
index fe10b617..6f132dd8 100644
--- a/doc/doxygen/Makefile.am
+++ b/doc/doxygen/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 all:
 	@echo -e \
 "Generate documentation:\n" \
diff --git a/doc/examples/Makefile.am b/doc/examples/Makefile.am
index 8a385ba8..7bb02dac 100644
--- a/doc/examples/Makefile.am
+++ b/doc/examples/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS  = .
 
 AM_CPPFLAGS = \
diff --git a/m4/Makefile.am b/m4/Makefile.am
index 15610fb1..165d2475 100644
--- a/m4/Makefile.am
+++ b/m4/Makefile.am
@@ -1 +1,2 @@
+# This Makefile.am is in the public domain
 EXTRA_DIST = libcurl.m4
diff --git a/src/Makefile.am b/src/Makefile.am
index b3f0df87..d496c95d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 if HAVE_CURL
 curltests = testcurl
 if HAVE_ZZUF
diff --git a/src/examples/Makefile.am b/src/examples/Makefile.am
index 9146c3a1..a01aa8d5 100644
--- a/src/examples/Makefile.am
+++ b/src/examples/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS  = .
 
 AM_CPPFLAGS = \
diff --git a/src/include/Makefile.am b/src/include/Makefile.am
index da0adcfd..437008fd 100644
--- a/src/include/Makefile.am
+++ b/src/include/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS = .
 
 if ENABLE_SPDY
diff --git a/src/microhttpd/Makefile.am b/src/microhttpd/Makefile.am
index 34a2e88c..a6632501 100644
--- a/src/microhttpd/Makefile.am
+++ b/src/microhttpd/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 AM_CPPFLAGS = \
   -I$(top_srcdir)/src/include \
   -I$(top_srcdir)/src/microhttpd
diff --git a/src/microspdy/Makefile.am b/src/microspdy/Makefile.am
index a1afb06c..7fb2c37f 100644
--- a/src/microspdy/Makefile.am
+++ b/src/microspdy/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 AM_CPPFLAGS = \
   -I$(top_srcdir)/src/include \
   -I$(top_srcdir)/src/microspdy
diff --git a/src/platform/Makefile.am b/src/platform/Makefile.am
index d97b5581..448efae3 100644
--- a/src/platform/Makefile.am
+++ b/src/platform/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 AM_CPPFLAGS = \
   -I$(top_srcdir)/src/include
 
diff --git a/src/spdy2http/Makefile.am b/src/spdy2http/Makefile.am
index df171dc2..f7432a9b 100644
--- a/src/spdy2http/Makefile.am
+++ b/src/spdy2http/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS  = .
 
 AM_CFLAGS =
diff --git a/src/testcurl/Makefile.am b/src/testcurl/Makefile.am
index 9346bed4..d418206d 100644
--- a/src/testcurl/Makefile.am
+++ b/src/testcurl/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS  = .
 
 if USE_COVERAGE
diff --git a/src/testcurl/https/Makefile.am b/src/testcurl/https/Makefile.am
index 2e81f3d0..47deb708 100644
--- a/src/testcurl/https/Makefile.am
+++ b/src/testcurl/https/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS = .
 
 if USE_COVERAGE
diff --git a/src/testspdy/Makefile.am b/src/testspdy/Makefile.am
index 43c1d5eb..9d78bec1 100644
--- a/src/testspdy/Makefile.am
+++ b/src/testspdy/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS  = .
 
 AM_CFLAGS = -DDATA_DIR=\"$(top_srcdir)/src/datadir/\"
diff --git a/src/testzzuf/Makefile.am b/src/testzzuf/Makefile.am
index dd023093..329fe04d 100644
--- a/src/testzzuf/Makefile.am
+++ b/src/testzzuf/Makefile.am
@@ -1,3 +1,4 @@
+# This Makefile.am is in the public domain
 SUBDIRS  = .
 
 if USE_COVERAGE