https://bugs.gentoo.org/773652
https://github.com/distcc/distcc/issues/440
https://github.com/distcc/distcc/commit/850db9eec0d5dd7f47ade8ffca91b679081f6d85

From 850db9eec0d5dd7f47ade8ffca91b679081f6d85 Mon Sep 17 00:00:00 2001
From: Alexey Sheplyakov <asheplyakov@altlinux.org>
Date: Sun, 11 Jul 2021 18:57:00 +0400
Subject: [PATCH] Improved cross-rewriting on non-x86 systems

Unfortunately autoconf and GCC don't agree on the system name:

- On arm (aarch64): `GNU_HOST` is `aarch64-unknown-linux-gnu`,
  and GCC triple is `aarch64-linux-gnu` instead.
- On rpm-based x86_64 distros: `GNU_HOST` is `x86_64-pc-linux-gnu`,
  and GCC triple is `x86_64-redhat-linux`

Therefore ask the compiler (when running distcc configure script)
how to correctly identify it.

Closes: #440
ALTBUG: 40425
--- a/configure.ac
+++ b/configure.ac
@@ -547,6 +547,22 @@ AC_SUBST(CPPFLAGS)
 AC_SUBST(POPT_INCLUDES)
 AC_SUBST(BUILD_POPT)
 AC_SUBST(GNOME_BIN)
+
+
+# Sometimes canonical triples as used by configure differ from GCC ones
+# x86: configure: x86_64-pc-linux-gnu, GCC: x86_64-linux-gnu
+# ALT Linux: configure: ${arch}-alt-linux-gnu, GCC: ${arch}-alt-linux
+# Therefore ask the compiler for its triple
+if test "x${GCC}" = xyes ; then
+	native_compiler_triple=`$CC -dumpmachine`
+fi
+if test "x$native_compiler_triple" = "x"; then
+	native_compiler_triple="$host"
+fi
+AC_MSG_NOTICE([Native compiler triple: $native_compiler_triple])
+
+AC_DEFINE_UNQUOTED(NATIVE_COMPILER_TRIPLE, ["$native_compiler_triple"], [Native compiler triple])
+
 AC_DEFINE_UNQUOTED(GNU_HOST, ["$host"], [Your gnu-style host triple])
 # The '.stamp-conf' files force creation of the containing directories in the
 # build tree.
--- a/src/compile.c
+++ b/src/compile.c
@@ -549,7 +549,7 @@ static void dcc_rewrite_generic_compiler(char **argv)
 static void dcc_add_clang_target(char **argv)
 {
         /* defined by autoheader */
-    const char *target = GNU_HOST;
+    const char *target = NATIVE_COMPILER_TRIPLE;
 
     if (strcmp(argv[0], "clang") == 0 || strncmp(argv[0], "clang-", strlen("clang-")) == 0 ||
         strcmp(argv[0], "clang++") == 0 || strncmp(argv[0], "clang++-", strlen("clang++-")) == 0)
@@ -577,7 +577,7 @@ static void dcc_add_clang_target(char **argv)
 static int dcc_gcc_rewrite_fqn(char **argv)
 {
         /* defined by autoheader */
-    const char *target_with_vendor = GNU_HOST;
+    const char *target_with_vendor = NATIVE_COMPILER_TRIPLE;
     char *newcmd, *t, *path;
     int pathlen = 0;
     int newcmd_len = 0;
@@ -595,11 +595,7 @@ static int dcc_gcc_rewrite_fqn(char **argv)
         return -ENOMEM;
     memset(newcmd, 0, newcmd_len);
 
-    if ((t = strstr(target_with_vendor, "-pc-"))) {
-        memcpy(newcmd, target_with_vendor, t - target_with_vendor);
-        strcat(newcmd, t + strlen("-pc"));
-    } else
-        strcpy(newcmd, target_with_vendor);
+    strcpy(newcmd, target_with_vendor);
 
 
     strcat(newcmd, "-");