See http://gcc.gnu.org/ml/gcc/2004-06/msg00394.html
This might fix the error

strstream.s: Assembler messages:
strstream.s:8390: Error: junk `(%ecx)' after expression
strstream.s:8402: Error: junk `(%ecx)' after expression
strstream.s:8551: Error: junk `(%ecx)' after expression
strstream.s:8563: Error: junk `(%ecx)' after expression
make[3]: *** [strstream.lo] Error 1
make[3]: Leaving directory `i686-unknown-linux-gnu/gcc-3.4.0-glibc-2.3.2/build-gcc/i686-unknown-linux-gnu/libstdc++-v3/src'

when building a cygwin->linux cross-compiler with gcc-3.4.0,
probably caused by patch to fix http://gcc.gnu.org/PR14808


--- gcc-3.4.0/gcc/cp/method.c.old	Sun Jun  6 22:46:04 2004
+++ gcc-3.4.0/gcc/cp/method.c	Sun Jun  6 22:48:13 2004
@@ -286,7 +286,7 @@
   tree alias;
   char buf[256];
 
-#if defined (__CYGWIN__) || defined (__MINGW32__)
+#if defined (TARGET_IS_PE_COFF)
   if (DECL_ONE_ONLY (function))
     return function;
 #endif
@@ -404,7 +404,7 @@
   push_to_top_level ();
 
 #if defined (ASM_OUTPUT_DEF) \
-  && !(defined (__CYGWIN__) || defined (__MINGW32__))
+  && !defined (TARGET_IS_PE_COFF)
   if (targetm.have_named_sections)
     {
       resolve_unique_section (function, 0, flag_function_sections);
--- gcc-3.4.0/gcc/config/i386/cygming.h.old	Sun Jun  6 22:50:46 2004
+++ gcc-3.4.0/gcc/config/i386/cygming.h	Sun Jun  6 22:52:10 2004
@@ -27,6 +27,8 @@
 
 #define TARGET_EXECUTABLE_SUFFIX ".exe"
 
+#define TARGET_IS_PE_COFF 1
+
 #include <stdio.h>
 
 /* Masks for subtarget switches used by other files.  */