[source] iw: fix build on musl host

[LEDE Commits]

stintel pushed a commit to source.git, branch master:
https://git.lede-project.org/c317af777b2924c3625768eaeaaf0e9bc5eb6cc3

commit c317af777b2924c3625768eaeaaf0e9bc5eb6cc3
Author: Stijn Tintel <stijn at linux-ipv6.be>
AuthorDate: Fri Sep 29 09:26:00 2017 +0300

    iw: fix build on musl host
    
    The empty version.sh script causes a problem when run by make:
    make[3]: /usr/bin/env bash: Shell program not found
    
    Adding a shebang line in version.sh seems to solve it.
    
    Fixes FS#977.
    
    Signed-off-by: Stijn Tintel <stijn at linux-ipv6.be>
---
 package/network/utils/iw/Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/package/network/utils/iw/Makefile b/package/network/utils/iw/Makefile
index a578ddc..9b3c12b 100644
--- a/package/network/utils/iw/Makefile
+++ b/package/network/utils/iw/Makefile
@@ -30,8 +30,7 @@ endef
 
 define Build/Configure
 	echo "const char iw_version[] = \"$(PKG_VERSION)\";" > $(PKG_BUILD_DIR)/version.c
-	rm -f $(PKG_BUILD_DIR)/version.sh
-	touch $(PKG_BUILD_DIR)/version.sh
+	echo "#!/bin/sh" > $(PKG_BUILD_DIR)/version.sh
 	chmod +x $(PKG_BUILD_DIR)/version.sh
 endef