configure.ac: Add user-friendly check for native x86_64-linux multilibs.

	* configure.ac: Add user-friendly check for native x86_64-linux
	multilibs.
	* configure: Regenerate.

From-SVN: r205975

1 files changed, 20 insertions, 0 deletions

diff --git a/configure b/configure
index d4a8213..749a35e 100755
--- a/configure
+++ b/configure
@@ -7500,6 +7500,26 @@ if test x${is_cross_compiler} = xyes ; then
   target_configargs="--with-cross-host=${host_noncanonical} ${target_configargs}"
 fi
 
+# Special user-friendly check for native x86_64-linux build, if
+# multilib is not explicitly enabled.
+case "$target:$have_compiler:$host:$target:$enable_multilib" in
+  x86_64-*linux*:yes:$build:$build:)
+    # Make sure we have a developement environment that handles 32-bit
+    dev64=no
+    echo "int main () { return 0; }" > conftest.c
+    ${CC} -m32 -o conftest ${CFLAGS} ${CPPFLAGS} ${LDFLAGS} conftest.c
+    if test $? = 0 ; then
+      if test -s conftest || test -s conftest.exe ; then
+	dev64=yes
+      fi
+    fi
+    rm -f conftest*
+    if test x${dev64} != xyes ; then
+      as_fn_error "I suspect your system does not have 32-bit developement libraries (libc and headers). If you have them, rerun configure with --enable-multilib. If you do not have them, and want to build a 64-bit-only compiler, rerun configure with --disable-multilib." "$LINENO" 5
+    fi
+    ;;
+esac
+
 # Default to --enable-multilib.
 if test x${enable_multilib} = x ; then
   target_configargs="--enable-multilib ${target_configargs}"