[tools] mklibs: upgrade to 0.1.37

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@36820 3c298f89-4303-0410-b956-a3cf2f4a3e73
[tools] gmp: upgrade to version 5.1.2

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@36821 3c298f89-4303-0410-b956-a3cf2f4a3e73
[tools] mpfr: upgrade to 3.1.2

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@36822 3c298f89-4303-0410-b956-a3cf2f4a3e73