diff --git a/docs/libcurl/libcurl.m4 b/docs/libcurl/libcurl.m4
index 8cada0523..d7d5a5259 100644
--- a/docs/libcurl/libcurl.m4
+++ b/docs/libcurl/libcurl.m4
@@ -146,7 +146,7 @@ AC_DEFUN([LIBCURL_CHECK_CONFIG],
            _libcurl_save_libs=$LIBS
            LIBS="$LIBCURL $LIBS"
 
-           AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <curl/curl.h>],[
+           AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <curl/curl.h>]],[[
 /* Try and use a few common options to force a failure if we are
    missing symbols or can't link. */
 int x;
@@ -158,7 +158,7 @@ x=CURLOPT_ERRORBUFFER;
 x=CURLOPT_STDERR;
 x=CURLOPT_VERBOSE;
 if (x) ;
-])],libcurl_cv_lib_curl_usable=yes,libcurl_cv_lib_curl_usable=no)
+]])],libcurl_cv_lib_curl_usable=yes,libcurl_cv_lib_curl_usable=no)
 
            CPPFLAGS=$_libcurl_save_cppflags
            LIBS=$_libcurl_save_libs