[pkgsrc/trunk]: pkgsrc/mk Improve USE_LANGUAGES explanation

[gdt <gdt%pkgsrc.org@localhost>]

details:   https://anonhg.NetBSD.org/pkgsrc/rev/d652b2928ddb
branches:  trunk
changeset: 364792:d652b2928ddb
user:      gdt <gdt%pkgsrc.org@localhost>
date:      Tue Jul 04 14:35:55 2017 +0000

description:
Improve USE_LANGUAGES explanation

Reference the notion of making compilers visible to the build
environment.  Mention setting --std flags.  Note that the text is
currently aspirtational relative to gcc and C++.

(Comment change only.)

diffstat:

 mk/compiler.mk |  12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diffs (30 lines):

diff -r c23de6757762 -r d652b2928ddb mk/compiler.mk
--- a/mk/compiler.mk    Tue Jul 04 14:35:49 2017 +0000
+++ b/mk/compiler.mk    Tue Jul 04 14:35:55 2017 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: compiler.mk,v 1.86 2017/06/10 11:32:32 kamil Exp $
+# $NetBSD: compiler.mk,v 1.87 2017/07/04 14:35:55 gdt Exp $
 #
 # This Makefile fragment implements handling for supported C/C++/Fortran
 # compilers.
@@ -40,12 +40,18 @@
 # The following variables may be set by a package:
 #
 # USE_LANGUAGES
-#      Lists the languages used in the source code of the package,
-#      and is used to determine the correct compilers to install.
+
+#      Declares the languages used in the source code of the package.
+#      This is used to determine the correct compilers to make
+#      visible to the build environment, installing them if
+#      necessary.  Flags such as --std=c++99 are also added.
 #      Valid values are: c, c99, c++, c++0x, gnu++0x, c++11, gnu++11,
 #      c++14, gnu++14, fortran, fortran77, java, objc, obj-c++, and
 #      ada.  The default is "c".
 #
+#       The above is partly aspirational.  As an example c++11 does
+#       not force a new enough version of gcc.
+
 # The following variables are defined, and available for testing in
 # package Makefiles:
 #