Search path environment variables for cross-compilers.  See the discussion
at <http://gcc.gnu.org/ml/gcc/2013-02/msg00124.html>.

Note: Touch 'C_INCLUDE_PATH' et al. rather than 'CPATH', as discussed
at <http://bugs.gnu.org/22186>.

--- a/gcc/incpath.c
+++ b/gcc/incpath.c
@@ -461,8 +461,8 @@ register_include_chains (cpp_reader *pfile, const char *sysroot,
 			 int stdinc, int cxx_stdinc, int verbose)
 {
   static const char *const lang_env_vars[] =
-    { "C_INCLUDE_PATH", "CPLUS_INCLUDE_PATH",
-      "OBJC_INCLUDE_PATH", "OBJCPLUS_INCLUDE_PATH" };
+    { "CROSS_C_INCLUDE_PATH", "CROSS_CPLUS_INCLUDE_PATH",
+      "CROSS_OBJC_INCLUDE_PATH", "CROSS_OBJCPLUS_INCLUDE_PATH" };
   cpp_options *cpp_opts = cpp_get_options (pfile);
   size_t idx = (cpp_opts->objc ? 2: 0);
 
@@ -473,7 +473,7 @@ register_include_chains (cpp_reader *pfile, const char *sysroot,
 
   /* CPATH and language-dependent environment variables may add to the
      include chain.  */
-  add_env_var_paths ("CPATH", BRACKET);
+  add_env_var_paths ("CROSS_CPATH", BRACKET);
   add_env_var_paths (lang_env_vars[idx], SYSTEM);
 
   target_c_incpath.extra_pre_includes (sysroot, iprefix, stdinc);
diff --git a/gcc/system.h b/gcc/system.h
index 42bc509..af3b9ad 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -1063,4 +1063,6 @@ helper_const_non_const_cast (const char *p)
 /* Get definitions of HOST_WIDE_INT and HOST_WIDEST_INT.  */
 #include "hwint.h"
 
+#define LIBRARY_PATH_ENV "CROSS_LIBRARY_PATH"
+
 #endif /* ! GCC_SYSTEM_H */
diff --git a/gcc/tlink.c b/gcc/tlink.c
index bc358b8..ad6242f 100644
--- a/gcc/tlink.c
+++ b/gcc/tlink.c
@@ -458,7 +458,7 @@ recompile_files (void)
   file *f;
 
   putenv (xstrdup ("COMPILER_PATH="));
-  putenv (xstrdup ("LIBRARY_PATH="));
+  putenv (xstrdup (LIBRARY_PATH_ENV "="));
 
   while ((f = file_pop ()) != NULL)
     {
diff --git a/gcc/gcc.c b/gcc/gcc.c
index adbf0c4..70448c6 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -3853,7 +3853,7 @@ process_command (unsigned int decoded_options_count,
     }
 
   temp = getenv (LIBRARY_PATH_ENV);
-  if (temp && *cross_compile == '0')
+  if (temp)
     {
       const char *startp, *endp;
       char *nstore = (char *) alloca (strlen (temp) + 3);