---
 gnu/packages/cross-base.scm                   |  2 +
 .../gcc-10-cross-environment-variables.patch  | 54 +++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644
gnu/packages/patches/gcc-10-cross-environment-variables.patch

diff --git a/gnu/packages/cross-base.scm b/gnu/packages/cross-base.scm
index 180594509b..0a93d0dc6d 100644
--- a/gnu/packages/cross-base.scm
+++ b/gnu/packages/cross-base.scm
@@ -243,6 +243,8 @@ (define* (cross-gcc target
         (append
          (origin-patches (package-source xgcc))
          (append (cond
+                  ((version>=? (package-version xgcc) "10.0")
+                    (search-patches
"gcc-10-cross-environment-variables.patch"))
                   ((version>=? (package-version xgcc) "8.0")
                    (search-patches
"gcc-8-cross-environment-variables.patch"))
                   ((version>=? (package-version xgcc) "6.0")
diff --git a/gnu/packages/patches/gcc-10-cross-environment-variables.patch
b/gnu/packages/patches/gcc-10-cross-environment-variables.patch
new file mode 100644
index 0000000000..829bc583e9
--- /dev/null
+++ b/gnu/packages/patches/gcc-10-cross-environment-variables.patch
@@ -0,0 +1,54 @@
+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>.
+
+diff --git a/gcc/gcc.c b/gcc/gcc.c
+index 9f790db0daf..326aa52f46f 100644
+--- a/gcc/gcc.c
++++ b/gcc/gcc.c
+@@ -4474,7 +4474,7 @@ process_command (unsigned int decoded_options_count,
+     }
+
+   temp = env.get (LIBRARY_PATH_ENV);
+-  if (temp && *cross_compile == '0')
++  if (temp)
+     {
+       const char *startp, *endp;
+       char *nstore = (char *) alloca (strlen (temp) + 3);
+diff --git a/gcc/incpath.c b/gcc/incpath.c
+index 8a2bda00f80..4f740a6a4c3 100644
+--- a/gcc/incpath.c
++++ b/gcc/incpath.c
+@@ -472,8 +472,8 @@ 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);
+
+@@ -484,7 +484,7 @@ 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", INC_BRACKET);
++  add_env_var_paths ("CROSS_CPATH", INC_BRACKET);
+   add_env_var_paths (lang_env_vars[idx], INC_SYSTEM);
+
+   target_c_incpath.extra_pre_includes (sysroot, iprefix, stdinc);
+diff --git a/gcc/system.h b/gcc/system.h
+index 263070169ab..14a819db28d 100644
+--- a/gcc/system.h
++++ b/gcc/system.h
+@@ -1248,4 +1248,6 @@ void gcc_stablesort (void *, size_t, size_t,
+    of the number.  */
+ #define PRsa(n) "%" #n PRIu64 "%c"
+
++#define LIBRARY_PATH_ENV "CROSS_LIBRARY_PATH"
++
+ #endif /* ! GCC_SYSTEM_H */
-- 
2.33.1