configure: indent error/warning message

Indent the error/warning message so that it is explicit that
the second line is giving details for the first general hint.

Reported-by: Titus von Boxberg <titus@v9g.de>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 --- binutils/ld/ldmain.c

 +++ binutils/ld/ldmain.c

 @@ -293,2 +293,3 @@ main (int argc, char **argv)

    link_info.combreloc = TRUE;

 +  link_info.relro = TRUE;

    link_info.strip_discarded = TRUE;