composer: platform independent + fix shebang

PHARs do not like to be edited after compilation, so shebang
has to be fixed before it was created.

packages/composer/build.sh

@@ -2,10 +2,12 @@ TERMUX_PKG_HOMEPAGE=https://getcomposer.org/
 TERMUX_PKG_DESCRIPTION="Dependency Manager for PHP"
 TERMUX_PKG_LICENSE="MIT"
 TERMUX_PKG_VERSION=2.0.8
+TERMUX_PKG_REVISION=1
 TERMUX_PKG_GIT_BRANCH=$TERMUX_PKG_VERSION
 TERMUX_PKG_SRCURL=https://github.com/composer/composer.git
 TERMUX_PKG_DEPENDS="php"
 TERMUX_PKG_BUILD_IN_SRC=true
+TERMUX_PKG_PLATFORM_INDEPENDENT=true
 
 termux_step_make_install() {
 	composer install

packages/composer/fix-shebang.patch

@@ -0,0 +1,13 @@
+diff --git a/src/Composer/Compiler.php b/src/Composer/Compiler.php
+index a31aff946..8398862a1 100644
+--- a/src/Composer/Compiler.php
++++ b/src/Composer/Compiler.php
+@@ -260,7 +260,7 @@ private function stripWhitespace($source)
+     private function getStub()
+     {
+         $stub = <<<'EOF'
+-#!/usr/bin/env php
++#!@TERMUX_PREFIX@/bin/env php
+ <?php
+ /*
+  * This file is part of Composer.