--- a/build/config/gcc/BUILD.gn
+++ b/build/config/gcc/BUILD.gn
@@ -78,16 +78,6 @@ config("relative_paths") {
   } else {
     cflags += [ "-fdebug-prefix-map=$absolute_path=$relative_path" ]
   }
-  cflags += [
-    # This makes sure that include directories in the toolchain are
-    # represented as relative to the build directory (because that's how
-    # we invoke the compiler), rather than absolute.  This can affect
-    # __FILE__ expansions (e.g. assertions in system headers).  We
-    # normally run a compiler that's someplace within the source tree
-    # (//buildtools/...), so its absolute installation path will have a
-    # prefix matching absolute_path and hence be mapped to relative_path
-    # in the debugging information, so this should actually be
-    # superfluous for purposes of the debugging information.
-    "-no-canonical-prefixes",
-  ]
+  # Gentoo uses native GCC reached through symlinks;
+  # omit -no-canonical-prefixes so driver resolves cc1/cc1plus.
 }
--- a/build/toolchain/linux/BUILD.gn
+++ b/build/toolchain/linux/BUILD.gn
@@ -10,6 +10,13 @@
 
 declare_args() {
   toolchain_prefix = ""
+  target_cc = ""
+  target_cxx = ""
+  target_ar = ""
+  target_nm = ""
+  target_readelf = ""
+  target_strip = ""
+  target_ld = ""
 }
 
 if (use_rbe) {
@@ -153,6 +160,9 @@ gcc_toolchain("clang_x64") {
 
 gcc_toolchain("x64") {
   prefix = ""
+  if (toolchain_prefix != "") {
+    prefix = toolchain_prefix
+  }
   asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
@@ -163,6 +173,29 @@ gcc_toolchain("x64") {
   ld = "${link_prefix}${prefix}g++"
   strip = "${prefix}strip"
 
+  if (target_cc != "") {
+    asm = target_cc
+    cc = "${compiler_prefix}${target_cc}"
+  }
+  if (target_cxx != "") {
+    cxx = "${compiler_prefix}${target_cxx}"
+  }
+  if (target_ar != "") {
+    ar = target_ar
+  }
+  if (target_nm != "") {
+    nm = target_nm
+  }
+  if (target_readelf != "") {
+    readelf = target_readelf
+  }
+  if (target_ld != "") {
+    ld = "${link_prefix}${target_ld}"
+  }
+  if (target_strip != "") {
+    strip = target_strip
+  }
+
   toolchain_cpu = "x64"
   toolchain_os = "linux"
   is_clang = false