[iagno] Depend on libm.

[Arnaud B. <arnaudb src gnome org>]

commit bcefbd666ae905db47e154b0d0e64e0fe6e25f77
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Mon Jul 22 18:12:42 2019 +0200

    Depend on libm.
    
    Copying a patch made by
    Jan Tojnar for 2048. If
    not specifying libm for
    building, linking might
    fail on a platform that
    separated it from libc.

 meson.build     | 5 ++++-
 src/meson.build | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 29f36c6..ee8c798 100644
--- a/meson.build
+++ b/meson.build
@@ -9,13 +9,16 @@ gnome = import('gnome')
 # used to run post install script
 python3 = import('python3')
 
+cc = meson.get_compiler('c')
+valac = meson.get_compiler('vala')
 
 canberra_dependency = dependency('libcanberra')
 canberra_gtk3_dependency = dependency('libcanberra-gtk3', version: '>= 0.26')
 gio_dependency = dependency('gio-2.0', version: '>= 2.40.0')
 glib_dependency = dependency('glib-2.0', version: '>= 2.40.0')
 gtk_dependency = dependency('gtk+-3.0', version: '>= 3.24.0')
-posix_dependency = meson.get_compiler('vala').find_library('posix')
+libm_dependency = cc.find_library('m', required: false) # some platforms do not have libm separated from libc
+posix_dependency = valac.find_library('posix')
 rsvg_dependency = dependency('librsvg-2.0', version: '>= 2.32.0')
 
 # Set gettext package name
diff --git a/src/meson.build b/src/meson.build
index f30803b..9e1f403 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -43,6 +43,7 @@ executable(meson.project_name(),
         gio_dependency,
         glib_dependency,
         gtk_dependency,
+        libm_dependency,
         posix_dependency,
         rsvg_dependency
     ]