cross-x86_64-linux-musl: update to 0.21.

- Do not remove SYSROOT/bin symlink.
- Update binutils, glibc/musl and linux headers.
- Sensible licenses=.

srcpkgs/cross-x86_64-linux-musl/template

@@ -1,30 +1,29 @@
 # Template build file for 'cross-x86_64-linux-musl'
 #
-_binutils_version=2.25
+_binutils_version=2.25.1
 _gcc_version=4.9.3
-_musl_version=1.1.10
-_linux_version=3.18.6
+_musl_version=1.1.12
+_linux_version=3.18.25
 
 _triplet=x86_64-linux-musl
 _sysroot="/usr/${_triplet}"
 
 pkgname=cross-${_triplet}
-version=0.20
-revision=4
+version=0.21
+revision=1
 short_desc="Cross toolchain for x86_64 with musl"
 maintainer="Juan RP <xtraeme@voidlinux.eu>"
 homepage="http://www.voidlinux.eu"
-license="Public Domain"
+license="GPL-3, GPL-2, MIT"
 distfiles="
  http://ftp.gnu.org/pub/gnu/binutils/binutils-${_binutils_version}.tar.bz2
  http://ftp.gnu.org/pub/gnu/gcc/gcc-${_gcc_version}/gcc-${_gcc_version}.tar.bz2
  http://www.kernel.org/pub/linux/kernel/v3.x/linux-${_linux_version}.tar.xz
  http://www.musl-libc.org/releases/musl-${_musl_version}.tar.gz"
-checksum="
- 22defc65cfa3ef2a3395faaea75d6331c6e62ea5dfacfed3e2ec17b08c882923
+checksum="b5b14added7d78a8d1ca70b5cb75fef57ce2197264f4f5835326b0df22ac9f22
  2332b2a5a321b57508b9031354a8503af6fdfb868b8c1748d33028d100a8b67e
- c4c1a4841173aa572d79b7530db92ce493dbefe8049e6f461a46dd897df253f5
- 45bbe9b1c7f7a0f743477af1e103b6889bfe4dd9815e16f6c89f6c90831c8b7c"
+ c649874e2856101df7cefe5fdad313ebb2282a939fc1e95cf02222327745ff92
+ 720b83c7e276b4b679c0bffe9509340d5f81fd601508e607e708177df0d31c0e"
 
 lib32disabled=yes
 nocross=yes
@@ -215,7 +214,7 @@ do_install() {
 	rm -rf ${DESTDIR}/${_sysroot}/usr/{sbin,share,libexec}
 	rm -f ${DESTDIR}/${_sysroot}/libexec
 	rm -f ${DESTDIR}/${_sysroot}/lib/*.py
-	rm -f ${DESTDIR}/${_sysroot}/{bin,sbin,lib}
+	rm -f ${DESTDIR}/${_sysroot}/{sbin,lib}
 }
 
 cross-x86_64-linux-musl-libc_package() {