Shared library config fix for MacOS X to make Ruby 1.9.3-p125 with XCode 4.3.x
happy.

https://bugs.ruby-lang.org/issues/6080

--- trunk/configure.in	2012/02/28 01:30:15	34839
+++ trunk/configure.in	2012/02/28 02:44:52	34840
@@ -289,12 +289,10 @@
 if test "$GCC" = yes; then
     linker_flag=-Wl,
     : ${optflags=-O3}
-    AS_CASE(["$target_os"], [linux*|darwin*], [: ${debugflags=-ggdb}])
     RUBY_APPEND_OPTIONS(XCFLAGS, ["-include ruby/config.h" "-include ruby/missing.h"])
 else
     linker_flag=
 fi
-test $ac_cv_prog_cc_g = yes && : ${debugflags=-g}
 
 RUBY_PROG_GNU_LD
 RUBY_CPPOUTFILE
@@ -490,6 +488,9 @@
     warnflags=
 fi
 if test "$GCC" = yes; then
+    test "${debugflags+set}" || {RUBY_TRY_CFLAGS(-ggdb, [debugflags=-ggdb])}
+    test "${debugflags+set}" || {RUBY_TRY_CFLAGS(-g3, [debugflags=-g3])}
+
     # -D_FORTIFY_SOURCE
     RUBY_TRY_CFLAGS(-D_FORTIFY_SOURCE=2, [RUBY_APPEND_OPTION(XCFLAGS, -D_FORTIFY_SOURCE=2)])
 
@@ -513,6 +514,7 @@
     # suppress annoying -Wstrict-overflow warnings
     RUBY_TRY_CFLAGS(-fno-strict-overflow, [RUBY_APPEND_OPTION(XCFLAGS, -fno-strict-overflow)])
 fi
+test $ac_cv_prog_cc_g = yes && : ${debugflags=-g}
 
 if test "$GCC" = ""; then
     AS_CASE(["$target_os"],[aix*],[warnflags="-qinfo=por"])