gnu: GCC: Switch to GCC 10.

* gnu/packages/patches/gcc-cross-gxx-include-dir.patch: New file.
* gnu/packages/patches/gcc-10-cross-environment-variables.patch: New file.
* gnu/packages/gcc.scm (gcc): Point to GCC-10.
(gcc-objc): Point to GCC-OBJC-10.
(gcc-objc++): Point to GCC-OBJC++-10.
* gnu/packages/cross-base.scm (cross-gcc)[source](patches): Apply the new
patches.

1 files changed, 51 insertions, 0 deletions

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..414198657d
--- /dev/null
+++ b/gnu/packages/patches/gcc-10-cross-environment-variables.patch
@@ -0,0 +1,51 @@
+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
+--- 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
+--- 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
+--- a/gcc/system.h
++++ b/gcc/system.h
+@@ -1244,4 +1244,6 @@ 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 */