Fix build with clang as system compiler.

/usr/include/c++/v1/exception:267:5: error: no member named 'fancy_abort' in namespace 'std::__1'; did you mean simply 'fancy_abort'?

Index: sources/tools/gcc/system.h
--- sources/tools/gcc/system.h.orig
+++ sources/tools/gcc/system.h
@@ -203,6 +203,7 @@ extern int errno;
 
 #ifdef __cplusplus
 # include <cstring>
+# include <new>
 #endif
 
 /* Some of glibc's string inlines cause warnings.  Plus we'd rather