[COMMITTED] configure: Fix bootstrap build after 570c46d36b (BZ 33985)

[Adhemerval Zanella]

The 570c46d36b make libgcc_s to be defined for have-cc-with-libunwind=noi
(default for gcc builds) without taking into consideration that the compiler
can link against -lgcc_s (defined by have-libgcc_s).

Checked with a build-many-glibc.py for x86_64-linux-gnu.
---
 Makeconfig | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Makeconfig b/Makeconfig
index ea509dd3bc..22dc7532f0 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -711,7 +711,9 @@ link-libc-static-tests = -Wl,--start-group $(common-objpfx)libc.a $(static-gnuli
 ifndef gnulib
 ifneq ($(have-cc-with-libunwind),yes)
   libunwind =
-  libgcc_s  = -lgcc_s
+  ifeq ($(have-libgcc_s),yes))
+    libgcc_s  = -lgcc_s
+  endif
 else
   libunwind = -lunwind $(libgcc-name)
   libgcc_s = $(libunwind)
-- 
2.43.0