[PATCH build] List environment variables with usage.

[Trevor Woerner]

From: Trevor Woerner <twoerner at gmail.com>

If help is requested using the build script, in addition to listing the
build command-line options available, also display the list of environment
variables which can be set which affect the build.

Signed-off-by: Trevor Woerner <twoerner at gmail.com>
---
 build.sh |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/build.sh b/build.sh
index d5884d8..ec5cc16 100755
--- a/build.sh
+++ b/build.sh
@@ -1,13 +1,17 @@
 #!/bin/sh
 
-# global environment variables you may set:
-# CACHE: absolute path to a global autoconf cache
-# QUIET: hush the configure script noise
-# CONFFLAGS: flags to pass to all configure scripts
-# CONFCFLAGS: flags to pass to all configure scripts in ""
-# MAKEFLAGS: flags to pass to all make calls
-# LIBDIR: Path under $prefix for libraries (e.g., lib64)
-# GITROOT: Path to freedesktop.org git root (default: git://anongit.freedesktop.org/git). Only needed for --clone
+envoptions() {
+cat << EOF
+global environment variables you may set:
+- CACHE: absolute path to a global autoconf cache
+- QUIET: hush the configure script noise
+- CONFFLAGS: flags to pass to all configure scripts
+- CONFCFLAGS: flags to pass to all configure scripts in ""
+- MAKEFLAGS: flags to pass to all make calls
+- LIBDIR: Path under \$prefix for libraries (e.g., lib64)
+- GITROOT: Path to freedesktop.org git root (default: git://anongit.freedesktop.org/git). Only needed for --clone
+EOF
+}
 
 failed_components=""
 nonexistent_components=""
@@ -681,6 +685,8 @@ usage() {
     echo "  --clone : clone non-existing repositories (uses \$GITROOT if set)"
     echo "  --autoresume file : autoresume from file"
     echo "  --check : run make check in addition to others"
+    echo ""
+    envoptions
 }
 
 HAVE_ARCH="`uname -i`"
-- 
1.7.1