diff --git a/configure.ac b/configure.ac
index a16031b5..a595cd98 100644
--- a/configure.ac
+++ b/configure.ac
@@ -640,7 +640,7 @@ case $enable_threads in
 		AC_CHECK_FUNCS([clock_gettime pthread_condattr_setclock])
 		AC_CHECK_DECL([CLOCK_MONOTONIC], [AC_DEFINE(
 			[HAVE_CLOCK_MONOTONIC], [1], [Define to 1 if
-			CLOCK_MONOTONIC is declared in <time.h>])], [],
+			`CLOCK_MONOTONIC' is declared in <time.h>.])], [],
 			[[#include <time.h>]])
 		CFLAGS=$OLD_CFLAGS
 		;;
diff --git a/m4/tuklib_progname.m4 b/m4/tuklib_progname.m4
index 2133e327..7685d068 100644
--- a/m4/tuklib_progname.m4
+++ b/m4/tuklib_progname.m4
@@ -23,6 +23,6 @@ AC_DEFUN_ONCE([TUKLIB_PROGNAME], [
 AC_REQUIRE([TUKLIB_COMMON])
 AC_CHECK_DECL([program_invocation_name], [AC_DEFINE(
 	[HAVE_PROGRAM_INVOCATION_NAME], [1],
-	[Define to 1 if PROGRAM_INVOCATION_NAME is declared in <errno.h>])],
+	[Define to 1 if `program_invocation_name' is declared in <errno.h>.])],
 	[], [#include <errno.h>])
 ])dnl