make.bash: document CC_FOR_${GOOS}_${GOARCH}

Fixes #51306

Change-Id: I5989d86fe5ac4d02793b2ecb00c549d9586763da
GitHub-Last-Rev: 6b0f6bee434219a2c502e8b5630fbe74ca25024a
GitHub-Pull-Request: golang/go#51379
Reviewed-on: https://go-review.googlesource.com/c/go/+/388176
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Trust: Cherry Mui <cherryyz@google.com>

diff --git a/src/make.bash b/src/make.bash
index 96cbbf37a919712e87600da99059f2fb1591a466..31387da33cfaab50ba081b719a66b369bdbf8a95 100755 (executable)
--- a/src/make.bash
+++ b/src/make.bash
@@ -41,12 +41,20 @@
 # Default is "gcc". Also supported: "clang".
 #
 # CC_FOR_TARGET: Command line to run to compile C code for GOARCH.
-# This is used by cgo.  Default is CC.
+# This is used by cgo. Default is CC.
+#
+# CC_FOR_${GOOS}_${GOARCH}: Command line to run to compile C code for specified ${GOOS} and ${GOARCH}.
+# (for example, CC_FOR_linux_arm)
+# If this is not set, the build will use CC_FOR_TARGET if appropriate, or CC.
 #
 # CXX_FOR_TARGET: Command line to run to compile C++ code for GOARCH.
 # This is used by cgo. Default is CXX, or, if that is not set,
 # "g++" or "clang++".
 #
+# CXX_FOR_${GOOS}_${GOARCH}: Command line to run to compile C++ code for specified ${GOOS} and ${GOARCH}.
+# (for example, CXX_FOR_linux_arm)
+# If this is not set, the build will use CXX_FOR_TARGET if appropriate, or CXX.
+#
 # FC: Command line to run to compile Fortran code for GOARCH.
 # This is used by cgo. Default is "gfortran".
 #