+GUIX_CHECK_GUILE_GCRYPT
+if test "x$guix_cv_have_recent_guile_gcrypt" != "xyes"; then
+ AC_MSG_ERROR([A recent Guile-Gcrypt could not be found; please install it.])
+fi
+
+GUIX_CHECK_GUILE_GIT
+if test "x$guix_cv_have_recent_guile_git" != "xyes"; then
+ AC_MSG_ERROR([A recent Guile-Git could not be found; please install it.])
+fi
+
+dnl Check for the optional Guile-Lib.
+GUILE_MODULE_EXPORTS([have_guile_lib], [(htmlprag)], [%strict-tokenizer?])
+AM_CONDITIONAL([HAVE_GUILE_LIB], [test "x$have_guile_lib" = "xyes"])
+AM_COND_IF(HAVE_GUILE_LIB,,
+ [AC_MSG_WARN([The Guile-Lib requirement was not satisfied (>= 0.2.7);
+Some features such as the Go importer will not be usable.])])
+
+dnl Check for Guile-zlib.
+GUIX_CHECK_GUILE_ZLIB
+if test "x$guix_cv_have_recent_guile_zlib" != "xyes"; then
+ AC_MSG_ERROR([A recent Guile-zlib could not be found; please install it.])
+fi
+
+dnl Check for Guile-lzlib.
+GUILE_MODULE_AVAILABLE([have_guile_lzlib], [(lzlib)])
+if test "x$have_guile_lzlib" != "xyes"; then
+ AC_MSG_ERROR([Guile-lzlib is missing; please install it.])
+fi
+
+dnl Check for Guile-Avahi.
+GUILE_MODULE_AVAILABLE([have_guile_avahi], [(avahi)])
+AM_CONDITIONAL([HAVE_GUILE_AVAHI],
+ [test "x$have_guile_avahi" = "xyes"])
+
+dnl Guile-newt is used by the graphical installer.
+GUILE_MODULE_AVAILABLE([have_guile_newt], [(newt)])
+
+AC_ARG_ENABLE([installer],
+ AS_HELP_STRING([--enable-installer], [Build the graphical installer sources.]))
+
+AS_IF([test "x$enable_installer" = "xyes"], [
+if test "x$have_guile_newt" != "xyes"; then
+ AC_MSG_ERROR([Guile-newt could not be found; please install it.])
+fi
+])
+
+AM_CONDITIONAL([ENABLE_INSTALLER],
+ [test "x$enable_installer" = "xyes"])
+