diff --git a/config.h.in b/config.h.in
index 11248c302..46769f5d4 100644
--- a/config.h.in
+++ b/config.h.in
@@ -531,11 +531,11 @@
 # define stat_sudoers	lstat
 #endif
 
-/* Solaris doesn't use const qualifiers in PAM. */
-#ifdef sun
-# define PAM_CONST
-#else
+/* Only OpenPAM and Linux PAM use const qualifiers. */
+#if defined(_OPENPAM) || defined(__LIBPAM_VERSION)
 # define PAM_CONST	const
+#else
+# define PAM_CONST
 #endif
 
 #ifdef USE_EXECV
diff --git a/configure.in b/configure.in
index 04f33748a..637989b9b 100644
--- a/configure.in
+++ b/configure.in
@@ -2175,11 +2175,11 @@ AH_BOTTOM([/*
 # define stat_sudoers	lstat
 #endif
 
-/* Solaris doesn't use const qualifiers in PAM. */
-#ifdef sun
-# define PAM_CONST
-#else
+/* Only OpenPAM and Linux PAM use const qualifiers. */
+#if defined(_OPENPAM) || defined(__LIBPAM_VERSION)
 # define PAM_CONST	const
+#else
+# define PAM_CONST
 #endif
 
 #ifdef USE_EXECV