diff --git a/guacd/configure.ac b/guacd/configure.ac
index dab2a341..7b7e51ae 100644
--- a/guacd/configure.ac
+++ b/guacd/configure.ac
@@ -40,7 +40,6 @@ AM_INIT_AUTOMAKE([-Wall -Werror foreign])
 
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/client.c])
-AC_CONFIG_HEADERS([include/client.h])
 
 # Programs
 AC_PROG_CC
diff --git a/libguac/configure.ac b/libguac/configure.ac
index 589831c5..414f175d 100644
--- a/libguac/configure.ac
+++ b/libguac/configure.ac
@@ -43,7 +43,6 @@ LT_INIT([dlopen])
 
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([src/protocol.c])
-AC_CONFIG_HEADERS([include/protocol.h])
 
 # Programs
 AC_PROG_CC
@@ -53,6 +52,10 @@ AC_PROG_LIBTOOL
 # Headers
 AC_CHECK_HEADERS([fcntl.h stdlib.h string.h sys/socket.h time.h sys/time.h syslog.h unistd.h cairo/cairo.h pngstruct.h])
 
+# Source characteristics
+AC_DEFINE([_POSIX_C_SOURCE], [199309L], [Uses POSIX APIs])
+AC_DEFINE([_BSD_SOURCE], [], [Uses BSD APIs])
+
 # Libraries
 AC_CHECK_LIB([dl], [dlopen],, AC_MSG_ERROR("libdl is required for loading client plugins"))
 AC_CHECK_LIB([png], [png_write_png],, AC_MSG_ERROR("libpng is required for writing png messages"))
@@ -73,10 +76,6 @@ AC_TYPE_SSIZE_T
 AC_CHECK_LIB([cunit], [CU_run_test], [CUNIT_LIBS=-lcunit])
 AC_SUBST(CUNIT_LIBS)
 
-# Defines
-AC_DEFINE(_POSIX_C_SOURCE, 199309L)
-AC_DEFINE(_BSD_SOURCE)
-
 AC_CONFIG_FILES([Makefile
                  src/Makefile
                  tests/Makefile])