[libgd/wip/meson] Don't explicitly require libm

[Zeeshan Ali <zeeshanak src gnome org>]

commit 872909ad0f647bb79b5392188b2a178e66f0002c
Author: Zeeshan Ali <zeenix gmail com>
Date:   Tue Oct 11 16:19:01 2016 +0200

    Don't explicitly require libm
    
    On many platforms libm is part of libc so requiring it will only fail the
    build.

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index b32ab98..f1de3d9 100644
--- a/meson.build
+++ b/meson.build
@@ -21,7 +21,7 @@ project('libgd', 'c')
 
 gtk = dependency('gtk+-3.0')
 cc = meson.get_compiler('c')
-libm = cc.find_library('libm')
+libm = cc.find_library('libm', required: false)
 
 sources = [ 'libgd/gd.h',
             'libgd/gd-types-catalog.c',