Gate mlkem.h include behind autoconf check

- Move AC_CHECK_HEADERS/AC_CHECK_LIB in configure.ac after wolfSSL
  path resolution
- Probe for wolfssl/wolfcrypt/mlkem.h in the header check list
- Guard mlkem.h include in src/internal.c with
  HAVE_WOLFSSL_WOLFCRYPT_MLKEM_H

Author: ejohnstown

configure.ac

@@ -55,11 +55,6 @@ AC_TYPE_SIZE_T
 AC_TYPE_UINT8_T
 AC_TYPE_UINTPTR_T
 
-# Check headers/libs
-AC_CHECK_HEADERS([limits.h sys/select.h sys/time.h sys/ioctl.h pty.h util.h termios.h])
-AC_CHECK_LIB([network],[socket])
-AC_CHECK_LIB([util],[forkpty])
-
 #wolfssl
 AC_MSG_CHECKING([for wolfSSL])
 if test "x$prefix" = "xNONE"
@@ -86,6 +81,10 @@ AC_ARG_WITH(wolfssl,
   ]
 )
 
+# Check headers/libs
+AC_CHECK_HEADERS([limits.h sys/select.h sys/time.h sys/ioctl.h pty.h util.h termios.h wolfssl/wolfcrypt/mlkem.h])
+AC_CHECK_LIB([network],[socket])
+AC_CHECK_LIB([util],[forkpty])
 AC_CHECK_LIB([wolfssl],[wolfCrypt_Init],,[AC_MSG_ERROR([libwolfssl is required for ${PACKAGE}. It can be obtained from https://www.wolfssl.com/download.html/ .])])
 AC_CHECK_FUNCS([gethostbyname getaddrinfo gettimeofday inet_ntoa memset socket wc_ecc_set_rng])
 AC_CHECK_DECLS([[pread],[pwrite]],,[unistd.h])

src/internal.c

@@ -57,7 +57,9 @@
 #endif
 
 #ifdef WOLFSSL_HAVE_MLKEM
-#include <wolfssl/wolfcrypt/mlkem.h>
+    #ifdef HAVE_WOLFSSL_WOLFCRYPT_MLKEM_H
+        #include <wolfssl/wolfcrypt/mlkem.h>
+    #endif
 #include <wolfssl/wolfcrypt/wc_mlkem.h>
 #endif