meson: elm: add pie and fPIC cflags and ldflags to elm binaries

My use case here is having elementary_test being loaded by exactness.
That has been working fine with our autotools based build system but no
longer with meson.

Bringing fPIC and pie back as options allows exactness to dlopen the
binary and work again.

Differential Revision: https://phab.enlightenment.org/D7587

Signed-off-by: Stefan Schmidt <s.schmidt@samsung.com>

src/bin/elementary/meson.build

@@ -157,7 +157,8 @@ elementary_test_src = [
 ]
 
 if sys_windows == false
-  link_args = '-rdynamic'
+  link_args = ['-rdynamic', '-fPIC', '-pie']
+  package_c_args =  package_c_args + ['-fPIC']
 else
   link_args = []
 endif