Disable -Wmissing-field-initializers to appease gcc 4.8.4
Disable -Wmissing-field-initializers to appease gcc 4.8.4

Unfortunately gcc 4.8.4 warns on "Foo foo = {}":

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36750

This appears to be fixed in gcc 5 but Travis uses gcc 4.8.4.

zeux/meshoptimizer,zeux/meshoptimizer,zeux/meshoptimizer