[PATCH v2 modular 1/1] build.sh: use the script name only, not the path in usage statement

[Gaetan Nadon]

If invoked from $PREFIX you currently you get:
Usage: util/modular/build.sh [options] prefix

Where you should always get:
Usage: build.sh [options] prefix

The path name is not part of the usage. The GNU compiler and
associated tools do not use the path.

Autoconf recommends using "expr" rather than "basename" for portability.

Signed-off-by: Gaetan Nadon <memsize at videotron.ca>
---
 build.sh |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/build.sh b/build.sh
index d6c946e..027c1c0 100755
--- a/build.sh
+++ b/build.sh
@@ -934,7 +934,8 @@ process_module_file() {
 }
 
 usage() {
-    echo "Usage: $0 [options] prefix"
+    basename="`expr "//$0" : '.*/\([^/]*\)'`"
+    echo "Usage: $basename [options] prefix"
     echo "  where options are:"
     echo "  -a : do NOT run auto config tools (autogen.sh, configure)"
     echo "  -b : use .build.$HAVE_ARCH build directory"
@@ -953,7 +954,7 @@ usage() {
     echo "  --cmd cmd : execute arbitrary git, gmake, or make command 'cmd'"
     echo "  --modfile file : only process the module/components specified in 'file'"
     echo ""
-    echo "Usage: $0 -L"
+    echo "Usage: $basename -L"
     echo "  -L : just list modules to build"
     echo ""
     envoptions
-- 
1.6.0.4